Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Phytophthora infestans
(Phytophthora blight)

Toolbox

Datasheet

Phytophthora infestans (Phytophthora blight)

Summary

  • Last modified
  • 11 December 2020
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Natural Enemy
  • Preferred Scientific Name
  • Phytophthora infestans
  • Preferred Common Name
  • Phytophthora blight
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Chromista
  •     Phylum: Oomycota
  •       Class: Oomycetes
  •         Order: Peronosporales

Don't need the entire report?

Generate a print friendly version containing only the sections you need.

Generate report

Pictures

Top of page
PictureTitleCaptionCopyright
Phytophthora infestans (Phytophthora blight); symptoms (late blight) on potato stem in the field.
TitleField symptoms
CaptionPhytophthora infestans (Phytophthora blight); symptoms (late blight) on potato stem in the field.
Copyright©Thorsten Kraska, University of Bonn, Germany
Phytophthora infestans (Phytophthora blight); symptoms (late blight) on potato stem in the field.
Field symptomsPhytophthora infestans (Phytophthora blight); symptoms (late blight) on potato stem in the field. ©Thorsten Kraska, University of Bonn, Germany
Phytophthora infestans (Phytophthora blight); leaf sporulation symptoms (late blight) on potato leaf in the field
TitleField symptoms
CaptionPhytophthora infestans (Phytophthora blight); leaf sporulation symptoms (late blight) on potato leaf in the field
Copyright©Thorsten Kraska, University of Bonn, Germany
Phytophthora infestans (Phytophthora blight); leaf sporulation symptoms (late blight) on potato leaf in the field
Field symptomsPhytophthora infestans (Phytophthora blight); leaf sporulation symptoms (late blight) on potato leaf in the field ©Thorsten Kraska, University of Bonn, Germany
Phytophthora infestans (Phytophthora blight); leaf sporulation symptoms (late blight) on potato leaf in the field.
TitleField symptoms
CaptionPhytophthora infestans (Phytophthora blight); leaf sporulation symptoms (late blight) on potato leaf in the field.
Copyright©Thorsten Kraska, University of Bonn, Germany
Phytophthora infestans (Phytophthora blight); leaf sporulation symptoms (late blight) on potato leaf in the field.
Field symptomsPhytophthora infestans (Phytophthora blight); leaf sporulation symptoms (late blight) on potato leaf in the field. ©Thorsten Kraska, University of Bonn, Germany
Phytophthora infestans (Phytophthora blight); symptoms of late blight on on upper surface of potato leaflets.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); symptoms of late blight on on upper surface of potato leaflets.
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); symptoms of late blight on on upper surface of potato leaflets.
SymptomsPhytophthora infestans (Phytophthora blight); symptoms of late blight on on upper surface of potato leaflets.©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); symptoms of late blight on on lower surface of potato leaflets.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); symptoms of late blight on on lower surface of potato leaflets.
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); symptoms of late blight on on lower surface of potato leaflets.
SymptomsPhytophthora infestans (Phytophthora blight); symptoms of late blight on on lower surface of potato leaflets.©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); symptoms of late blight: infection of potato and Solanum nigrum.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); symptoms of late blight: infection of potato and Solanum nigrum.
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); symptoms of late blight: infection of potato and Solanum nigrum.
SymptomsPhytophthora infestans (Phytophthora blight); symptoms of late blight: infection of potato and Solanum nigrum.©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); symptoms of late blight.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); symptoms of late blight.
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); symptoms of late blight.
SymptomsPhytophthora infestans (Phytophthora blight); symptoms of late blight.©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); symptoms of late blight on a potato stem.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); symptoms of late blight on a potato stem.
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); symptoms of late blight on a potato stem.
SymptomsPhytophthora infestans (Phytophthora blight); symptoms of late blight on a potato stem.©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); leaflets are blighted due to infection.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); leaflets are blighted due to infection.
Copyright©Mauritius Sugar Industry Research Institute
Phytophthora infestans (Phytophthora blight); leaflets are blighted due to infection.
SymptomsPhytophthora infestans (Phytophthora blight); leaflets are blighted due to infection.©Mauritius Sugar Industry Research Institute
Phytophthora infestans (Phytophthora blight); symptoms on tomato.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); symptoms on tomato.
Copyright©CAB International/Rob Williams
Phytophthora infestans (Phytophthora blight); symptoms on tomato.
SymptomsPhytophthora infestans (Phytophthora blight); symptoms on tomato.©CAB International/Rob Williams
Phytophthora infestans (Phytophthora blight); stem lesions and wilted leaves on an infected potato plant infected.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); stem lesions and wilted leaves on an infected potato plant infected.
Copyright©William E. Fry
Phytophthora infestans (Phytophthora blight); stem lesions and wilted leaves on an infected potato plant infected.
SymptomsPhytophthora infestans (Phytophthora blight); stem lesions and wilted leaves on an infected potato plant infected.©William E. Fry
Phytophthora infestans (Phytophthora blight); late blight of tomato fruit.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); late blight of tomato fruit.
Copyright©Anna L. Snowdon
Phytophthora infestans (Phytophthora blight); late blight of tomato fruit.
SymptomsPhytophthora infestans (Phytophthora blight); late blight of tomato fruit.©Anna L. Snowdon
Phytophthora infestans (Phytophthora blight); symptoms on tomato fruit. Lesions are firm, large, irregular, brownish-green blotches; the lesion surface has a greasy rough appearance.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); symptoms on tomato fruit. Lesions are firm, large, irregular, brownish-green blotches; the lesion surface has a greasy rough appearance.
Copyright©Thomas A. Zitter
Phytophthora infestans (Phytophthora blight); symptoms on tomato fruit. Lesions are firm, large, irregular, brownish-green blotches; the lesion surface has a greasy rough appearance.
SymptomsPhytophthora infestans (Phytophthora blight); symptoms on tomato fruit. Lesions are firm, large, irregular, brownish-green blotches; the lesion surface has a greasy rough appearance. ©Thomas A. Zitter
Phytophthora infestans (Phytophthora blight); blighted potato tubers, showing typical reddish-brown 'marbling' of infected flesh.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); blighted potato tubers, showing typical reddish-brown 'marbling' of infected flesh.
Copyright©Anna L. Snowdon
Phytophthora infestans (Phytophthora blight); blighted potato tubers, showing typical reddish-brown 'marbling' of infected flesh.
SymptomsPhytophthora infestans (Phytophthora blight); blighted potato tubers, showing typical reddish-brown 'marbling' of infected flesh.©Anna L. Snowdon
Phytophthora infestans (Phytophthora blight); blight infected potato tubers exhibit wet and dry rots.
TitleSymptoms
CaptionPhytophthora infestans (Phytophthora blight); blight infected potato tubers exhibit wet and dry rots.
Copyright©William E. Fry
Phytophthora infestans (Phytophthora blight); blight infected potato tubers exhibit wet and dry rots.
SymptomsPhytophthora infestans (Phytophthora blight); blight infected potato tubers exhibit wet and dry rots.©William E. Fry
Phytophthora infestans (Phytophthora blight); lemon-shaped sporangia (29-36 x 19-22µm) on sporangiophores.
TitleSporangia
CaptionPhytophthora infestans (Phytophthora blight); lemon-shaped sporangia (29-36 x 19-22µm) on sporangiophores.
Copyright©R.V. James
Phytophthora infestans (Phytophthora blight); lemon-shaped sporangia (29-36 x 19-22µm) on sporangiophores.
SporangiaPhytophthora infestans (Phytophthora blight); lemon-shaped sporangia (29-36 x 19-22µm) on sporangiophores.©R.V. James
Phytophthora infestans (Phytophthora blight); sporangia.
TitleSporangia
CaptionPhytophthora infestans (Phytophthora blight); sporangia.
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); sporangia.
SporangiaPhytophthora infestans (Phytophthora blight); sporangia.©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (late blight); Sporangia. March 2021.
TitleSporangia
CaptionPhytophthora infestans (late blight); Sporangia. March 2021.
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (late blight); Sporangia. March 2021.
SporangiaPhytophthora infestans (late blight); Sporangia. March 2021.©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (late blight); Sporangia. March 2021.
TitleSporangia
CaptionPhytophthora infestans (late blight); Sporangia. March 2021.
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (late blight); Sporangia. March 2021.
SporangiaPhytophthora infestans (late blight); Sporangia. March 2021.©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (late blight); Oospores. March 2021.
TitleOospores
CaptionPhytophthora infestans (late blight); Oospores. March 2021.
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (late blight); Oospores. March 2021.
OosporesPhytophthora infestans (late blight); Oospores. March 2021.©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); oospores.
TitleOospores
CaptionPhytophthora infestans (Phytophthora blight); oospores.
Copyright©Richard Shattock
Phytophthora infestans (Phytophthora blight); oospores.
OosporesPhytophthora infestans (Phytophthora blight); oospores.©Richard Shattock
Phytophthora infestans (Phytophthora blight); experimental plantings of potato hybrids without any chemical
treatments (control) and plantings of potato hybrids treated with fungicides (variants), to protect them from the disease, during severe epidemics (Russia, Moscow region).
TitleExperimental potato hybrids
CaptionPhytophthora infestans (Phytophthora blight); experimental plantings of potato hybrids without any chemical treatments (control) and plantings of potato hybrids treated with fungicides (variants), to protect them from the disease, during severe epidemics (Russia, Moscow region).
Copyright©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology
Phytophthora infestans (Phytophthora blight); experimental plantings of potato hybrids without any chemical
treatments (control) and plantings of potato hybrids treated with fungicides (variants), to protect them from the disease, during severe epidemics (Russia, Moscow region).
Experimental potato hybridsPhytophthora infestans (Phytophthora blight); experimental plantings of potato hybrids without any chemical treatments (control) and plantings of potato hybrids treated with fungicides (variants), to protect them from the disease, during severe epidemics (Russia, Moscow region).©Maria A. Kuznetsova - All-Russian Research Institute of Phytopathology

Identity

Top of page

Preferred Scientific Name

  • Phytophthora infestans (Mont.) de Bary

Preferred Common Name

  • Phytophthora blight

International Common Names

  • English: blight of potato; downy mildew of potato; late blight of potato; late blight of tomato; potato blight; potato late blight
  • Spanish: mildiu de la patata; mildiu del tomate; tizon tardio
  • French: mildiou de la pomme de terre; mildiou de la tomate
  • Russian: fitoftoros
  • Chinese: wan yi bing
  • Portuguese: mela da batata; requeima da batata

Local Common Names

  • Germany: Braunfaeule: Kartoffel; Braunfaeule: Tomate; Kraut und Knollenfaeule: Kartoffel; Krautfaeule: Tomate
  • India: aaloo ka jhulsa
  • Ukraine: phytophthorosis

EPPO code

  • PHYTIN (Phytophthora infestans)

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Chromista
  •         Phylum: Oomycota
  •             Class: Oomycetes
  •                 Order: Peronosporales
  •                     Family: Peronosporaceae
  •                         Genus: Phytophthora
  •                             Species: Phytophthora infestans

Notes on Taxonomy and Nomenclature

Top of page
The taxonomic understanding of species of Phytophthora and related organisms has been improving rapidly (Brasier, 1992; Brasier and Hansen, 1992). It is now clear that oomycete fungi are not related to ascomycete and basidiomycete fungi. Erwin and Ribeiro (1996) discussed the change in understanding of the taxonomic position of this group of organisms. It has long been held that organisms producing zoospores with two, unequal flagella are closely related. This characteristic includes the genus Phytophthora as well as some algae. In some classification schemes these organisms were grouped into the large kingdom Protoctista. However, a recent classification scheme, discussed by Erwin and Ribeiro, is that of Dick (1995a, b) in which the kingdom Chromista is supported. The genus Phytophthora occurs within the family Pythiaceae, which is included either in the phylum Oomycota or the phylum Peronosporomycota, depending upon interpretation. However, regardless of the groupings of more general taxa, it is very clear that the genus Phytophthora, the closely related genus Pythium, and the downy mildews (i.e. Bremia, Sclerospora, Peronospora, etc.) are unrelated to ascomycetes and basidiomycetes.

Description

Top of page
P. infestans is a coenocytic oomycete with rare cross walls. Asexual reproduction is via sporangia that are ellipsoid to lemon shaped with a small pedicel. Sporangia are 29-36 x 19-22 µm. Sporangia germinate either directly to form a germ tube (at temperatures of 15-24°C), or indirectly via zoospores (at temperatures below 18°C). Zoospores (ca 7-12 per sporangium) have two flagella, one forward-directed tinsel type and a backward-directed whiplash type (heterokont). Zoospores are usually uninucleate, but binucleate zoospores have been detected.

In culture, the mycelium is white and fluffy; the colony is somewhat slow growing. Growth rates can vary dramatically among isolates, but fast-growing isolates can cover a 9-cm plate within 7-10 days. Some isolates produce a lumpy appearance: this has sometimes been associated with the A2 mating type.

Oogonia rare in host or single culture, but developing promptly on pairing isolates of opposite compatibility type, 38 (max. 50) µm diameter, tapering at base. Antheridia amphigynous, elongated cylindrical, 17 (max. 22) x 16 µm. Oospores average 30 µm, aplerotic, wall 3-4 µm (Stamps, 1985).

Distribution

Top of page

P. infestans is intimately associated with its potato host and has apparently travelled around the world with potatoes (Cox and Large, 1960; Fry et al., 1993).

Potato tubers are readily infected and seed tubers are distributed all around the world, thus the occurrence of P. infestans is sometimes more closely allied to the distribution of seed tubers than to an indigenous pathogen population that survives in the absence of its agricultural hosts. Any location that receives seed tubers from an area where late blight is present is thus also likely to have late blight. Most locations in Asia, South-East Asia and Australia, Africa, the Americas and Europe can have late blight, especially if seed tubers are imported from an area where late blight is persistent. Thus, one location can have a population of P. infestans in one year, but not the next. Alternatively, a location could be free of late blight in one year, but have it the next. Locations that might reliably avoid late blight are those at very northerly or southerly latitudes, and at particularly high altitudes. Similarly, some lowland tropical locations are persistently too warm for late blight. Reports of the disease, therefore, do not necessarily imply an indigenous population of the pathogen. Instead, such reports indicate that the climate can support growth of this oomycete at least in some growing seasons.

Recent Migrations of P. infestans

Until the 1980s, only the A1 mating type of P. infestans was widely and commonly distributed (Goodwin et al., 1994b). Both mating types (A1 and A2) were common in Mexico, but were apparently not common in other locations. Outside Mexico, populations of P. infestans were dominated by a particular clonal lineage (US-1) (Goodwin et al., 1994b). This situation changed dramatically during the 1980s and 1990s. Isolates of P. infestans with the A2 mating type were first reported from Switzerland (Hohl and Iselin, 1984) and subsequently from many countries in northern Europe (Fry et al., 1993). Isolates with the A2 mating type are also reported to be found in Russia (Kuznetsova et al., 2013). Subsequently, isolates with A2 mating type were reported from Japan and Korea. By the early 1990s, isolates with A2 mating type were common throughout the USA and Canada (Fry et al., 1993). In addition to A2 mating types, isolates of A1 mating type that were quite different from US-1 began to appear in other locations worldwide (Colombia, Ecuador, USA, Canada, western Europe, Burundi and Rwanda) (Fry and Goodwin, 1995).

The occurrence of exotic strains of P. infestans (A1 and/or A2) indicates migrations of P. infestans. The primary origin of these exotic strains is Mexico in all cases where an origin can be ascribed. In many locations, the exotic strains are associated with an increased severity of late blight on potatoes and/or tomatoes (Spielman et al. 1991; Goodwin et al., 1994b, 1995b). After a very long time in which P. infestans populations had been asexual, sexual reproduction has become a component of the life history of this organism in parts of western Europe and the USA and Canada (Sujkowski et al., 1994; Drenth et al., 1995; Goodwin et al., 1995b).

Distribution Table

Top of page

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 25 Feb 2021
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes

Africa

AlgeriaPresent
AngolaPresent
CameroonPresent
EgyptPresent
EthiopiaPresent
GhanaPresent
KenyaPresent
MadagascarPresent
MalawiPresent
MauritiusPresent
MoroccoPresent
NigeriaPresent
RéunionPresent
RwandaPresent
SomaliaPresent
South AfricaPresent
SudanPresent
TanzaniaPresent
UgandaPresent
ZambiaPresent
ZimbabwePresent

Asia

AzerbaijanPresent
BangladeshPresent
ChinaPresent
-BeijingPresent
-ChongqingPresent
-FujianPresent
-GansuPresent
-GuangxiPresent
-GuizhouPresent
-HainanPresent
-HebeiPresent
-HeilongjiangPresent
-Inner MongoliaPresent
-JiangsuPresent
-JilinPresent
-LiaoningPresent
-QinghaiPresent
-ShanxiPresent
-SichuanPresent
-YunnanPresent
GeorgiaPresent
IndiaPresent
-AssamPresent
-BiharPresent
-HaryanaPresent
-Himachal PradeshPresent
-Jammu and KashmirPresent
-MaharashtraPresent
-MeghalayaPresent
-PunjabPresent
-Tamil NaduPresent
-Uttar PradeshPresent
-UttarakhandPresent
-West BengalPresent
IndonesiaPresent
IranPresent
IraqPresent
IsraelPresent
JapanPresent
JordanPresent
KazakhstanPresent
LaosPresent
LebanonPresent
MalaysiaPresent
NepalPresent
North KoreaPresent
PakistanPresent
PhilippinesPresent
Saudi ArabiaPresent
South KoreaPresent
Sri LankaPresent
TaiwanPresent
ThailandPresent
TurkeyPresent
VietnamPresent

Europe

AustriaPresent
BelarusPresent
BelgiumPresent
Bosnia and HerzegovinaPresent
BulgariaPresent
CyprusPresent
CzechiaPresent
CzechoslovakiaPresent
Federal Republic of YugoslaviaPresent
DenmarkPresent
EstoniaPresent
FinlandPresent
FrancePresent
GermanyPresent
GreecePresent
HungaryPresent
IcelandPresent
IrelandPresent
ItalyPresent
-SicilyPresent
LatviaPresent
LithuaniaPresent
LuxembourgPresent
MaltaPresent
MoldovaPresent
NetherlandsPresent
North MacedoniaPresent
NorwayPresent
PolandPresent
PortugalPresent
-AzoresPresent
RomaniaPresent
RussiaPresent
-Russia (Europe)Present
-SiberiaPresent
SerbiaPresent
SlovakiaPresent
SloveniaPresent
SpainPresent
SwedenPresent
SwitzerlandPresent
UkrainePresent
United KingdomPresent
-Channel IslandsPresent
-EnglandPresent
-ScotlandPresent
-WalesPresent

North America

Antigua and BarbudaPresent
BahamasPresent
BarbadosPresent
BermudaPresent
CanadaPresentPresent based on regional distribution.
-AlbertaPresent
-British ColumbiaPresent
-ManitobaPresent
-New BrunswickPresent
-Newfoundland and LabradorPresent
-Nova ScotiaPresent
-OntarioPresent
-Prince Edward IslandPresent
-QuebecPresent
-SaskatchewanPresent2010
Costa RicaPresent
CubaPresent
DominicaPresent
Dominican RepublicPresent
El SalvadorPresent
GuadeloupePresent
GuatemalaPresent
HaitiPresent
HondurasPresent
JamaicaPresent
MartiniquePresent
MexicoPresent
MontserratPresent
NicaraguaPresent
PanamaPresent
Puerto RicoPresent
Saint Kitts and NevisPresent
Saint LuciaPresent
Saint Vincent and the GrenadinesPresent
Trinidad and TobagoPresent
United StatesPresentPresent based on regional distribution.
-AlabamaPresent
-AlaskaPresent
-ArizonaPresent
-ArkansasPresent
-CaliforniaPresent
-ColoradoPresent
-ConnecticutPresent
-DelawarePresent
-FloridaPresent
-GeorgiaPresent
-HawaiiPresent
-IdahoPresent
-IllinoisPresent
-IndianaPresent
-IowaPresent
-KansasPresent
-KentuckyPresent
-LouisianaPresent
-MainePresent
-MarylandPresent
-MassachusettsPresent
-MichiganPresent
-MinnesotaPresent
-MississippiPresent
-MissouriPresent
-MontanaPresent
-NebraskaPresent
-New HampshirePresent
-New JerseyPresent
-New MexicoPresent
-New YorkPresent
-North CarolinaPresent
-North DakotaPresent
-OhioPresent
-OklahomaPresent
-OregonPresent
-PennsylvaniaPresent
-Rhode IslandPresent
-South CarolinaPresent
-South DakotaPresent
-TennesseePresent
-TexasPresent
-VermontPresent
-VirginiaPresent
-WashingtonPresent
-West VirginiaPresent
-WisconsinPresent
-WyomingPresent

Oceania

American SamoaPresent
AustraliaPresentPresent based on regional distribution.
-New South WalesPresent
-QueenslandPresent
-South AustraliaPresent
-VictoriaPresent
-Western AustraliaPresent
Cook IslandsPresent
FijiPresent
New CaledoniaPresent
New ZealandPresent
Norfolk IslandPresent
Papua New GuineaPresent
SamoaPresent

South America

ArgentinaPresent
BoliviaPresent
BrazilPresent
-BahiaPresent
-Distrito FederalPresent
-Espirito SantoPresent
-GoiasPresent
-Minas GeraisPresent
-ParaibaPresent
-ParanaPresent
-Rio Grande do SulPresent
-Santa CatarinaPresent
-Sao PauloPresent
ChilePresent
ColombiaPresent
EcuadorPresent
GuyanaPresent
ParaguayPresent
PeruPresent
UruguayPresent
VenezuelaPresent

Risk of Introduction

Top of page
Risk Criteria Category

Economic Importance High
Distribution Worldwide
Seedborne Incidence Low
Seed Transmitted Yes
Seed Treatment Yes

Overall Risk High


Notes on phytosanitary risk

Until very recently, there were strict controls on the movement of exotic strains of P. infestans. Typically, locations that did not have the A2 mating type prohibited import of potatoes from locations with the A2 mating type. The very recent and rapid distribution of isolates of A2 mating type (Fry et al., 1993) has stimulated a re-evaluation of that policy. Nonetheless, different strains of P. infestans have different characteristics and it may still be important to restrict or reduce rapid distribution of this pathogen.

Hosts/Species Affected

Top of page
Although generally considered to have a limited host range and to be a near-biotrophic pathogen, P. infestans has been reported to cause infection on a large number of species. Erwin and Ribeiro (1996) list 89 host species, but more than 25% of these were included because artificial inoculations resulted in lesions. In agriculture, the two most important hosts are potatoes and tomatoes.

P. infestans is a potentially devastating pathogen on potatoes in almost all locations where they are grown (Cox and Large, 1960). It is also a serious pathogen on tomatoes in cooler climates. In addition to these globally important agricultural crops, P. infestans attacks wild and cultivated species of Solanum in the Americas. It is reported on a large number of species of Solanum in central Mexico (Rivera-Pena and Molina-Galan, 1989), on hairy nightshade (Solanum sarrachoides) throughout the Americas, and on pear melons (S. muricatum) in the Andes of South America (Turkensteen, 1978).

Some populations of P. infestans have been identified that favour one host over another. In Ecuador, two populations of P. infestans exist which can be distinguished by isoenzyme patterns for glucose-6-phospahte isomerase (Erselius et al., 2000). One population (EC-1) is only found on potato and the other population (US-1) is only found on tomato. Similar preferences were also reported from isolates collected in France and the USA (Legard et al., 1995; Lebreton et al., 1999).

Isolates of the genus Phytophthora closely related to infestans have also been found in South America on Solanum betaceum, a tree fruit, and on the wild species Solanum brevifolium and Solanum tetrapetalum (Ordoñez et al., 2000). These isolates are morphologically identical to P. infestans but represent novel genotypes based on analyses with neutral genetic markers. For this reason, the taxonomy of these isolates is uncertain.

Although P. infestans has been associated with many hosts it is not clear to what extent these hosts may be attacked in nature by the same pathogen genotype. Separate genotypes have been associated with different hosts in South America (Erselius et al., 1999) and even with potato and tomato in different parts of the world (Oyarzun et al., 1998; Vega-Sanchez et al., 2000). Therefore, although the host range of P. infestans is potentially wide, many pathogen genotypes may be specific to certain hosts.

Host Plants and Other Plants Affected

Top of page
Plant nameFamilyContextReferences
Capsicum annuum (bell pepper)SolanaceaeOther
Capsicum frutescens (chilli)SolanaceaeOther
Datura metel (Hindu datura)SolanaceaeWild host
Datura stramonium (jimsonweed)SolanaceaeWild host
Hyoscyamus niger (black henbane)SolanaceaeWild host
Ipomoea purpurea (tall morning glory)ConvolvulaceaeWild host
Lycium barbarum (Matrimonyvine)SolanaceaeWild host
LycopersiconSolanaceaeUnknown
Lycopersicon pimpinellifolium (currant tomato)SolanaceaeOther
Nicotiana glauca (tree tobacco)SolanaceaeWild host
PetuniaSolanaceaeWild host
Petunia hybridaSolanaceaeWild host
Pharbitis nil (Japanese morning glory)ConvolvulaceaeWild host
Physalis angulata (cutleaf groundcherry)SolanaceaeWild host
Physalis ixocarpaSolanaceaeOther
Physalis peruviana (Cape gooseberry)SolanaceaeOther
Rumex acetosa var. hortensis (garden sorrel)PolygonaceaeWild host
Solanum (nightshade)SolanaceaeWild host
Solanum cardiophyllumSolanaceaeOther
Solanum demissumSolanaceaeOther
Solanum dulcamara (bittersweet nightshade)SolanaceaeOther
Solanum ehrenbergiiSolanaceaeOther
Solanum incanum (grey bitter-apple)SolanaceaeWild host
Solanum indicumSolanaceaeWild host
Solanum laciniatum (kangaroo apple)SolanaceaeWild host
Solanum lycopersicum (tomato)SolanaceaeMain
Goodwin et al. (1999); Goodwin et al. (1995)
Solanum marginatum (white-edged nightshade)SolanaceaeWild host
Solanum melongena (aubergine)SolanaceaeWild host
Solanum muricatum (melon pear)SolanaceaeOther
Solanum muricatum (melon pear)SolanaceaeOther
Solanum nigrum (black nightshade)SolanaceaeWild host
Solanum physalifoliumSolanaceaeOther
Solanum sarrachoides (green nightshade)Other
Goodwin et al. (1995)
Solanum sisymbriifolium (sticky nightshade)SolanaceaeUnknown
Solanum stoloniferumSolanaceaeOther
Solanum tuberosum (potato)SolanaceaeMain
Solanum verrucosumSolanaceaeOther
Solanum viarum (tropical soda apple)SolanaceaeOther

Growth Stages

Top of page
Flowering stage, Fruiting stage, Post-harvest, Pre-emergence, Seedling stage, Vegetative growing stage

Symptoms

Top of page
The symptoms of late blight on potatoes and tomatoes may vary, depending on the age of the lesion and the immediate preceding environment (previous 12 h). Very young lesions on potato or tomato foliage appear as irregularly shaped, small (2-10 mm) lesions with or without a small surrounding area of collapsed but still green tissue. Lesions later turn brown. Older lesions are larger and assume a circular appearance unless delimited by the leaflet margin. They are usually not delimited by the veins. Older lesions are typically surrounded by a zone of collapsed tissue that is not yet necrotic. The non-necrotic tissue may also appear somewhat chlorotic. If there are many lesions on a single leaflet, the entire leaf can turn chlorotic.

Sporulation may be evident on the collapsed tissue and on the outermost portions of the necrotic areas of a lesion if it has been in a saturated atmosphere (100% RH) for more than 7 or 8 h. The length of time required for sporulation is dependent on temperature and host resistance. On resistant cultivars, sporulation might not appear until some hours after it would appear on a susceptible cultivar. Optimal temperature for sporulation is usually regarded to be 15-20°C. Temperatures above or below this range will reduce the rate of pathogen growth and thus extend the time required for sporulation. Under optimal conditions for sporulation it is easily visible as a noticeable fuzzy white growth on lesion margins. Sporulation occurs from lesions whether they are on leaflets or on stems.

When the immediately preceding conditions have been dry, there is no sporulation and the lesions may appear dried up with no remnants of sporulation.

Blighting of the entire plant (even entire fields) occurs during moist warm periods. Patches of infected plants have a characteristic odour.

Infected potato tubers exhibit wet and dry rots. On tomato fruits, lesions are firm, large, irregular, brownish-green blotches; the lesion surface has a greasy, rough appearance.

List of Symptoms/Signs

Top of page
SignLife StagesType
Fruit / lesions: black or brown
Leaves / abnormal colours
Leaves / fungal growth
Leaves / necrotic areas
Leaves / wilting
Vegetative organs / dry rot
Vegetative organs / soft rot
Whole plant / seedling blight
Whole plant / unusual odour

Biology and Ecology

Top of page
Where P. infestans exists as an asexual organism it is essentially an obligate parasite. It requires a living host (crop debris or solanaceous weeds) for long-term survival. Whereas sporangia may survive days or weeks in soil, they cannot overwinter or overseason. Mycelium of the fungus cannot survive in the absence of a living host cell. However, in locations where sexual reproduction occurs, the resulting oospore can survive for months or years in the absence of living hosts (Drenth et al., 1995).

Asexual Life History

The details of infection have been known for decades (Crosier, 1934). Infections usually start from sporangia which germinate either directly via a germ tube or indirectly via zoospores. Zoospores can swim for some minutes, after which time they encyst and germinate. A germ tube penetrates a living host and establishes a near-biotrophic relationship for the first few days in a compatible interaction. If the interaction is incompatible, host cells die rapidly (hypersensitive response). In the compatible interaction, lesions become visible within a few days; the exact time is dependent on temperature and host resistance. Under optimal conditions (18-22°C), infections can be visible in less than 3 days.

Within a day or two after the lesion first becomes visible, the fungus is capable of sporulation. Moderate temperatures (10-25°C) and very wet conditions (leaf wetness or 100% RH) are required for sporulation. Sporangia are borne on sporangiophores within 8-12 h during favourable conditions. Sporangia secede during changing relative humidity and can be captured in air currents; they can also be splash dispersed. They can survive for hours in unsaturated atmospheres when protected from solar radiation (Minogue and Fry, 1981), so dispersal distances of hundreds of metres or kilometres are possible (Van der Zaag, 1956). Sporangia landing on a host can germinate and penetrate living cells within 2 h under favourable conditions. In most cases, however, germination and penetration require more than 2 h. Under favourable conditions, large numbers of sporangia can be produced from a single lesion (more than 100, 000 sporangia per lesion) (Legard et al., 1995); the disease can thus progress rapidly under cool, wet conditions.

Potato tubers (surviving in soil, surviving in storage, or surviving in dumps or other locations for discarded materials) are very important in the survival of the asexual phase of P. infestans. Infected tubers that are protected from freezing in the cold temperate zones harbour viable P. infestans. If these tubers are planted or if plants are produced from these tubers, the fungus can again sporulate under favourable conditions and initiate a new series of asexual generations.

Seed tubers are crucial in the long-distance dispersal of P. infestans. It seems highly likely that they were the vehicle for transport of P. infestans in the very earliest migrations (19th century). Detection of exotic genotypes in seed tubers shipped across a continent (2000 km) and in subsequent epidemics in plants produced from those seed tubers (WE Fry, Cornell University, USA, unpublished results) confirms that tubers shipped very long distances have transported P. infestans, and intercontinental transport seems highly likely.

Tuber infections are highly variable from place to place, from one year to the next, and among cultivars. However infections as high as 60-80% are possible. More typically, low percentages of tubers are infected (not detectable to 2-3%). The probability that any given tuber will initiate a new epidemic on foliage is quite low. But because of the very high reproductive potential of this organism, a very low rate of transfer of pathogens from tubers to new foliage can still lead to devastating epidemics. Infection of potato tubers (especially seed tubers) is crucially important in long-distance dispersal of P. infestans. Conditions that enable the tuber to survive also enable the pathogen to survive. When that tuber gets to another location and is placed in conditions that favour the fungus (moderate temperatures and high moisture), the fungus can resume activity. It can sporulate directly on a potato tuber. If the tuber is planted or otherwise buried in the ground, the fungus can sporulate from the tuber and grow up the stem or perhaps be splash dispersed by rain-drops from the tuber in soil. When sporangia contact host tissue, the cycles of infection can be resumed.

Sexual Life History

When individuals of opposite mating type (A1 and A2) come into physical contact, sexual structures (antheridia and oogonia) are produced by each thallus. Meiosis is gametangial. After fertilization, the oogonium develops into an oospore which can survive adverse conditions better than the hyphae or sporangia. After a period of dormancy (weeks or months), oospores become capable of germination. Germination in the laboratory can occur on water agar at 18°C in the presence of blue light. It is clear that oospores can survive winter in northern temperate zones (Drenth et al., 1995), but the precise conditions stimulating germination are not yet known. Oospores germinate via a germ sporangium. This sporangium can then germinate via zoospores or via a germtube. If the fungus contacts a host plant it can initiate the asexual phase.

Natural enemies

Top of page
Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Bacillus subtilis Pathogen Russia
Colletotrichum coccodes Pathogen Russia
Pseudomonas putida Pathogen Russia

Notes on Natural Enemies

Top of page
There is very little work reported on natural enemies of P. infestans, and none has been employed in managing this oomycete.

Seedborne Aspects

Top of page
Incidence

P. infestans has long been known to be seedborne on tomato (Reed, 1912; Boyd, 1935). Vartanian and Endo (1985a) recovered the pathogen from seeds at incidences of up to 93% when seeds were plated directly on selective medium after harvesting from blighted fruit. However, the recovery rate dropped to 0% when the seeds were air-dried for 72 hours at 22°C. Histological studies on freshly harvested seeds showed that the pathogen was present in the gel surrounding the seed, in the seed coat, in the funiculus and between the endosperm and seed coat (Vartanian and Endo, 1985a). Rubin et al. (2001) showed that abundant oospores developed in the vascular tissues, pericarp, columella, and placenta of tomato fruits at the mature green stage, when coinoculated with A1 + A2 sporangia of P. infestans. Oospores were also formed on the surface of fruits kept in a moisture-saturated atmosphere. Occasionally, oospores were enclosed between the epidermal hairs of the seed coat. In a few seeds, oospores were detected inside the embryo.

P. infestans has not been reported as seedborne on true seeds of potato. However, it is seedborne on tuber seed pieces. Tuber infections are highly variable from place to place, from one year to the next and among cultivars. However, infections as high as 60-80% are possible. More typically, low percentages of tubers are infected (not detectable to 2-3%). The probability that any given tuber will initiate a new epidemic on foliage is quite low. However, because of the very high reproductive potential of P. infestans, a very low rate of transfer of the pathogen from tubers to new foliage can still lead to devastating epidemics.

Effect on Seed Quality

Infected seeds recovered from blighted tomato fruits were discoloured (Vartanian and Endo, 1985a).

Pathogen Transmission

Seed

Transmission of P. infestans to tomato seedlings at rates of 34 and 18% was demonstrated for moist, discoloured seeds in sterilized soil in the greenhouse and under field conditions in natural soil, respectively. No transmission of the pathogen was found in the greenhouse or field for moist, non-discoloured seeds or from discoloured seeds that had been air-dried before planting (Vartanian and Endo, 1985a).

Other sources

Potato and tomato crop residues provide an overwintering source of P. infestans, which then sporulates and can be transmitted by wind to tomato plants (Vartanian and Endo, 1985a, b).

Infection of potato tubers (especially seed tubers) is crucially important in long-distance dispersal of P. infestans. Conditions that enable the tuber to survive also enable the pathogen to survive. When that tuber is placed in conditions that favour the fungus (moderate temperatures and high moisture), the fungus can resume activity. It can sporulate directly on a potato tuber. If the tuber is planted or otherwise buried in the ground, the fungus can sporulate from the tuber and grow up the stem or perhaps be splash dispersed by rain-drops from the tuber in soil. When sporangia contact host tissue, the cycles of infection can be resumed.

Seed Treatment

Fermentation reduced seedborne infection of tomato seeds, but air-drying for 72 hours at 22°C or oven-drying for 6 hours at 29-5-37.7°C was needed to eliminate the pathogen (Vartanian and Endo, 1985a).

Potato tuber infections probably result from sporangia that have been washed from foliage through the soil to the tuber. Theoretically, tuber infections can be prevented by systemic fungicides if the pathogen is sensitive to these fungicides. For example, metalaxyl was very effective at preventing tuber infections caused by metalaxyl-sensitive strains of P. infestans (Fry et al., 1979). However, metalaxyl has almost no effect against strains that are insensitive. A number of materials have recently been evaluated for efficacy as protective seed treatments for late blight. Dimethomorph plus mancozeb, cymoznil plus mancozeb, and propamocarb hydrochloride plus chlorothalonil had increased stand emergence when inoculum was applied following seed treatments (Powelson and Inglis, 1999).

Seed Health Tests

Culture plate (Vartanian and Endo, 1985a)

- Place tomato seeds on rye seed agar, supplemented with pimaricin, ampicillin, rifampicin and pantachlronitrobenzene.
- Incubate at 21°C in the dark and evaluate plates at 1, 2, 5 and 14 days.

Plant Trade

Top of page
Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Bulbs/Tubers/Corms/Rhizomes fungi/hyphae; fungi/spores Yes Yes Pest or symptoms usually visible to the naked eye
Flowers/Inflorescences/Cones/Calyx fungi/hyphae; fungi/spores Yes Yes Pest or symptoms usually visible to the naked eye
Fruits (inc. pods) fungi/hyphae; fungi/spores Yes Yes Pest or symptoms usually visible to the naked eye
Leaves fungi/hyphae; fungi/spores Yes Yes Pest or symptoms usually visible to the naked eye
Stems (above ground)/Shoots/Trunks/Branches fungi/hyphae; fungi/spores Yes Yes Pest or symptoms usually visible to the naked eye
True seeds (inc. grain) fungi/hyphae Yes Yes Pest or symptoms usually invisible
Plant parts not known to carry the pest in trade/transport
Bark
Growing medium accompanying plants
Roots
Seedlings/Micropropagated plants
Wood

Impact

Top of page

Introduction

Late blight of potatoes or tomatoes can be a devastating disease with dramatic and disastrous economic consequences. It is known as the most devastating disease of potatoes and one of the most devastating plant diseases of any crop. When conditions favour pathogen development and there are no steps taken to suppress the disease, late blight can completely destroy the above-ground parts of plants (stems, leaves, tomato fruits) and can also affect potato tubers. The disease is a very serious economic threat in the vast majority of potato-production systems, and in many tomato-production systems. In locations where disease pressure is high, protectant fungicides may need to be applied as frequently as twice per week.

The Irish potato famine provides a grim indication of the destructive potential of P. infestans. The disease was first detected in Ireland in 1845 and for the succeeding several years it devastated the potato crops (Bourke, 1993). More than a million Irish died from starvation and at least another million emigrated. The population of Ireland declined steadily after 1845 from a high of about 8.5 million to just over half that by the end of the nineteenth century.

The Global Late Blight Initiative

The International Potato Center, known by its Spanish acronym, CIP, has made an attempt at estimating global losses due to potato late blight. The information that follows can be found on the CIP web page.

The acceptance of the late-blight-resistant cultivars to be developed under the global late blight initiative (GILB) is consistent with the economic benefits to be derived by reducing fungicide inputs and crop damage in developing countries. For the purpose of projecting potential returns on investment, CIP has conservatively estimated current losses from late blight at approximately 15% of annual production in developing countries. Assuming that a third of global potato production now occurs in developing countries (FAO/CIP, 1995), an equivalent or proportional share of these losses must occur there as well. Thus, 15% of one-third of 275 million tons (annual global potato production) is equivalent to 13.75 million tons. According to the CGIAR Technical Advisory Committee, a reasonable estimate of global producer prices for potatoes is US$200 per ton. Hence, the annual economic value of crop losses from late blight in developing countries is said to total $2.75 billion. In 1976, late-blight-related crop losses occurred despite increases in fungicide use. At the time, estimated global fungicide costs exceeded $1 billion annually. Again, for the purpose of the GILB, CIP conservatively estimates current fungicide costs to be on the order of $100 million annually in developing countries, that is, an average of $15 per hectare. Hence, crop losses (production forgone) and increased costs (expenses incurred) for late blight begin to approach the $3 billion mark. It should be noted that these figures represent only current losses.

Crop Losses

Europe

Late blight is a major problem throughout Northern and Eastern Europe. In Poland it causes significant losses (Piekarczyk and Babilas, 1986) that have been estimated at about 22% (Pietkiewicz, 1991). In Romania, in experiments conducted in 1982, there were losses of about 40% on the susceptible cultivar Bintje and losses of between 6 and 30% on other cultivars (Cupsa et al., 1983). In 1990 late blight was reported as increasing in importance as potato acreage increased (Bicici and Cinar, 1990). Late blight was reported to cause severe losses due to the presence of the A2 mating type as well as increased specific virulence and fungicide resistance of the pathogen (Kuznetsova et al., 2013).

The severity of late blight was recently reported to be increasing in Hungary, but quantitative data were not given. The increased severity was associated with the presence of the A2 mating type, as well as increased specific virulence and fungicide resistance of the pathogen population (Bakonyi and Ersek, 1997).

In Denmark, yield losses were simulated for pesticide-free agricultural systems. Losses due to potato late blight were among the highest of all crop systems considered, indicating the potential destructiveness of this disease in that country (Jorgensen et al., 1999).

Africa

Fungicide use comprises one of the simplest ways to estimate economic loss attributed to a disease and therefore is frequently used in developing countries. A survey done in Eastern African countries in the early 1990s (Kalyebara, 1994) demonstrated that fungicide use in this part of the world was highly variable, even among neighboring countries. In Zaire, fungicides were almost never used, in Burundi somewhat more and in Rwanda, most farmers sprayed at least 3 times. In Kenya, commercial farmers sprayed 5-7 times; smaller semi-commercial farmers spray 3-5 times. The most common product was Dithane, but Ridomil was used to some extent. Although production losses were not estimated in this survey one can probably assume to some degree an inverse relationship between fungicide use and losses; in those countries where fungicides were used more, production losses would be less. Workers in those parts of the world and even recent simulation efforts indicate that fungicides are generally poorly utilized, and frequently under-utilized in sub-Saharan Africa (Hijmans et al., 2000).

This view is consistent with a study undertaken in Burundi in 1989-90, where 32,000 t of potatoes were produced on 10,000 ha of land. Late blight was the most important disease causing yield losses up to 40% (Higiro and Danial, 1994).

Late blight is also important in western Africa. Yield reductions were found to vary between 25 and 71% in experiments done in Cameroon in 1990 and 1991. These data reflect comparisons of fungicide-treated and untreated plots under experimental conditions. Disease was more severe in Bansoa than it was in Dschang (Fontem and Aighewi, 1993).

Asia

Experiments conducted in India demonstrated loss potential of 39 and 37% due to late blight in two consecutive years. Two sprays of fungicide were able to control disease in these years (Rao and Veeresh, 1989). Bisht (Bisht et al., 1997) estimated that yield losses can be much higher, about 65%, in higher altitudes of India.

Yield losses in Bhutan were estimated as between 20 and 90%, but this was for a complex of disease including late blight, early blight (Alternaria solani), wart (Synchytrium endobioticum), black scurf (Rhizoctonia solani), brown rot (Ralstonia solanacearum), blackleg (Erwinia carotovora subsp. atroseptica) and potato virus Y (Shrestha et al., 1986).

Late blight was apparently introduced recently in Pakistan (Khan et al., 1985). At that time (1980s) it caused complete crop loss in some cases, presumably due in part to lack of control measures. Workers in the region indicate that late blight is still an important problem (CIP, unpublished data).

Andean region

Fungicides cost Andean farmers a lot of money. A recent survey estimated costs of about $150.00 per ha for a single season (Ortiz et al., 1999). This survey, however, was done in a particularly dry period and probably underestimates costs. The cost of spraying a field 15 times, which is not uncommon during rainy periords, would be closer to $600.00, depending on the type of fungicides used.

Based also on farm surveys, Andrade and Revelo (1994) estimated losses in Ecuador in 1992 to be about US$ 2.4 million. They added that 1992 was a dry year and that this figure would double in a wet year. Ecuador is probably a good indicator for fungicide use in other Andean countries.

USA

The economic consequences were estimated for one epidemic occurring in 1995 in the Columbia Basin of the state of Washington in the USA. The mean number of fungicide applications per field varied from 5.1 to 12.3, depending on cultivar. Total per acre expenses (application costs plus fungicide material) ranged from $106.77 to $226.85, depending on cultivar and location. Approximately 28% of the crop was chemically desiccated before harvest as a disease management practice for the first time in 1995, resulting in an additional mean cost of $34.48/acre or $1.3 million for the region. Harvested yields were 4 to 6% less than in 1994. The total cost of managing late blight in the Columbia Basin in 1995 is estimated to have approached $30 million (Johnson et al., 1997).

Avoiding Crop Losses

Avoiding disease can be an effective disease management strategy. Farmers in the Andes plant susceptible potatoes at high altitudes where low temperatures reduce late blight pressure (Thurston, 1994). However, this strategy is frequently used in such a way that farmers trade off yield potential for decreased risk of disease. One survey in Ecuador estimated that between 30 and 40% of potato production in the province of Cotopaxi (central Ecuador) was done in the dry season to avoid late blight (Instituto Nacional de Investigación Agropecuaria, unpublished data). Yields in the dry season are considerably lower. Similarly, much of the potato production in the highlands of Ethiopia occurs during a period known as the "short rains". Yields are low during this period because of limited water supply, but the risk of losses due to blight is also reduced. Overall production in this country could be increased by the introduction of potato cultivars with resistance to late blight that could be planted in the main rainy season.

Late Blight on other Hosts

Late blight can be a devastating disease of tomato. Although tomato is generally an intensively-cultivated crop and farmers therefore justify the expense of fungicides, several factors make late blight a particularly difficult problem. First, there is very little resistance available in commercial tomato cultivars (Oyarzun et al., 1998), which means that with favourable weather conditions it is difficult to manage the disease even with fungicides. Second, unlike potato, the edible portion of tomato is directly exposed to fungicide applications. This complicates management practices near harvest time. Finally, pathogen populations from tomato and potato appear to be separate and adapted only to one host (Oyarzun et al., 1998). This means that tomato workers can not readily apply information gathered on the pathogen population from potato. Late blight is the most important disease of tomato in some developing countries.

P. infestans (or a very closely related species) is a pathogen of other cultivated hosts that only occur in specific regions of the world. One host is tree tomato (Solanum betaceum), which is economically important in certain parts of the Andes. Late blight of tree tomato appears to be important in specific climatic zones. In one valley in Ecuador known as San Jose de Minas, tree tomato production was abandoned because of late blight. Late blight of pear melon (S. muricatum) is also a limiting factor for producers in the Andes. The pathogen populations of tree tomato and pear melon are also host adapted and do not pose a threat to potato. Both tree tomato and pear melon are cultivated outside of the Andean region but it is not known if blight attacks these crops in other parts of the world.

Diagnosis

Top of page
Lesions may be incubated in a moist chamber for 12-24 h: the subsequent characteristic sporulation may be observed.

P. infestans can grow on a variety of culture media, but not all isolates will grow on all media. Commonly used media are rye agar, V-8 juice agar, pea agar, cornmeal agar, corn seed agar, and lima bean agar. A listing of recipes is presented in Erwin and Ribeiro (1996).

Diagnostic kits or techniques that employ biochemical or molecular methods may be helpful. Diagnostic kits, such as enzyme-linked immunosorbent assay (ELISA) that rely on antibody-antigen reactions may not be sensitive to species and may cross-react with Pythium, but can provide initial indication of the presence of an oomycete. Amplification of DNA using the polymerase chain reaction (PCR) may be helpful. Some primers for PCR are apparently specific to P. infestans (Trout et al., 1997) and their use in diagnosis should be helpful. Alloenzyme markers have been used to detect specific genotypes of the fungus in certain simple clonal populations (Goodwin et al., 1995a).

Detection and Inspection

Top of page
For potatoes, the first plant parts to be inspected should be the seed tubers. Lesions can be readily seen on clean tubers with smooth white skins. Lesions are more difficult to detect on russeted or pigmented tubers. External inspection should be followed by observation of the flesh just underneath the periderm. Late blight causes a corky, 'granular', apparently discontinuous dry rot. Sometimes the rot penetrates only a few millimetres into the flesh; however, in other situations, or on other cultivars, the rot may extend for 1, 2 or 3 cm. Soft rot may follow infection by P. infestans and soft rot can sometimes overtake the late blight. The fungus will typically sporulate from tuber lesions if the tubers are placed in a moist chamber for 24 h at 18°C: positive confirmation of sporulation is often sufficient for diagnosis.

When the crop is growing, lesions can appear on any plant part. Typically, lesions are most likely to occur on plants in the wettest locations. These could be in a low spot in a field, or in locations that are shaded or that are likely to remain wet longer than other locations in the field. If a fungicide is used, the disease may appear first on plants that are difficult to spray with fungicide. The initial lesions can appear on stems or leaflets: on upper leaflets (presumably from an aerially dispersed sporangia), on upper stem segments, or on lower leaflets or lower stem segments (perhaps from an infected seed tuber). In locations where sexual reproduction is possible, the soil can serve as a source of inoculum and the first infections might again appear in the lower part of the canopy (leaves or stems).

If lesions are observed under dry conditions, diagnosis from visual symptoms may be more difficult. Incubation of lesions in a moist chamber for 12-24 h and subsequent observation for the characteristic sporulation is quite helpful.

Similarities to Other Species/Conditions

Top of page
Late blight lesions can be mistaken for several other diseases. Under especially wet conditions, Botrytis cinerea can rot lower leaves of potato plants such that they resemble late blight lesions. However, the sporulation from B. cinerea is noticeably grey rather than white as for P. infestans. When conditions become quite dry and late blight lesions dry out, they can be mistaken for dried lesions caused by B. cinerea or sometimes for lesions caused by Alternaria solani (early blight). However, early blight lesions are typically zonate with a definite outer margin, whereas active late blight lesions are almost never zonate and typically do not have a definite outer margin.

Prevention and Control

Top of page

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Introduction

Both reduction in the amount of initial inoculum and suppression of pathogen growth rates are important in the suppression of late blight of potatoes and tomatoes. At this point, there is no biological control of known efficacy for use in suppressing late blight. Several fungicides have been shown to have a curative effect in tuber-borne P. infestans (Inglis et al., 1999). Thiophanate-methyl plus mancozeb applied to blighted potato seed pieces reduced the amount of surface colonized by P. infestans and when planted had higher emergence in two locations.

Reduce Initial Inoculum

For potatoes, it is important to plant healthy seed tubers, so that the pathogen is not imported with seed tubers. Other sources of inoculum in a growing region should be eliminated. These include any place where infected potato tubers might reside: piles of cull potatoes, or unharvested potato tubers that survive from one season to the next. Because sporangia of P. infestans can be dispersed aerially, late blight is a 'communal' disease. It is important that all growers in a production region collaborate to eliminate sources of inoculum. If this doesn't happen, a few fields with infected plants can jeopardize production in an entire region.

Tuber infections can be limited by increasing the depth of the soil barrier that protects the tubers. This can be achieved by constructing deep hills over the tubers to lessen the probability of tuber infections. Theoretically, tuber infections can be prevented by systemic fungicides when the pathogen is sensitive to those fungicides. For example metalaxyl was very effective at preventing tuber infections caused by metalaxyl-sensitive strains of P. infestans (Fry et al., 1979). However metalaxyl has almost no effect against strains that are insensitive.

Limit Pathogen Growth Rates

Late-blight-resistant cultivars and periodic application of fungicides limit pathogen growth rates. Both are effective and can be used together. In some agroecosystems, cultivars with very high levels of resistance are available and these alone are sufficient to suppress late blight. In other locations, such highly resistant cultivars are not available, and fungicides are also required. Note that some fungal strains are insensitive to some fungicides such as metalaxyl.

Many 'forecasting' schemes have been developed to improve the efficiency with which fungicides are used (Van Everdingen, 1926; Beaumont, 1947; de Weille, 1964; Krause and Massie, 1975; Connell et al., 1991; Filippov et al., 2019). Most of these schemes identify when the first applications of protectant fungicide should be made in each season; such schemes operate in areas of defined seasons and not in the highland tropics where planting can occur throughout the year. In general, such schemes have successfully identified when periodic protectant fungicide applications should commence. Some forecasting schemes have also attempted to identify the subsequent frequency of fungicide applications. The efficacy of this approach is less certain.

If a hot spot of late blight appears in a field, growers should destroy that section of the field as rapidly as possible and perhaps also increase the frequency of fungicide application in surrounding areas.

References

Top of page

Andrade H, Revelo J, 1994. Breve diagnóstico de la problemática del cultivo de papa, con énfasis en resistencia a enfermedades. In: Proceedings of Primer Taller Sobre Resistencia Duradera en Cultivos Alto Andinos. Quito, Ecuador: INIBAP

Andrivon, D., Pilet, F., Montarry, J., Hafidi, M., Corbière, R., Achbani, E., Pellé, R., Ellissèche, D., 2007. Adaptation of Phytophthora infestans to partial resistance in potato: evidence from French and Moroccan populations. Phytopathology, 97(3), 338-343. doi: 10.1094/PHYTO-97-3-0338

Arti Shukla, Gupta SK, Sharma HR, 2013. Occurrence of late blight in cherry tomato grown under protected conditions in Himachal Pradesh. Plant Disease Research, 28(2):205-206. http://insopp.org.in/

Bakonyi J, Trsek T, 1997. A threat of potato late blight in Hungary. No^umlaut~ve^acute~nyve^acute~delem, 33(5):221-228; 20 ref

Beaumont A, 1947. The dependence on the weather of the dates of outbreak of potato blight epidemics. Transactions of the British Mycological Society, 31:45-53

Bekele Kassa, Sommartya T, 2006. Effect of intercropping on potato late blight, Phytophthora infestans (Mont.) de Bary development and potato tuber yield in Ethiopia. Kasetsart Journal, Natural Sciences, 40(4):914-924

Bicici M, Cinar A, 1990. A review of Phytophthora diseases of different Mediterranean crops in Turkey. Bulletin OEPP, 20(1):101-105

Bisht GS, Harish S, Singh H, Sati SC, Saxena J, Dubey RC, 1997. Fungal diseases of useful plants in the Garhwal Himalaya and their management. Himalayan Microbial Diversity, Part 1, 255-271

Bourke A, 1993. 'The visitation of god?' The potato and the great Irish famine. Dublin, Irish Republic: Lilliput Press Ltd., 230 pp

Boyd OC, 1935. Evidence of seeed-borne nature of late blight of tomato. Phytopathology, 25:7

Brasier CM, 1992. Evolutionary biology of Phytophthora. Part I: genetic system, sexuality and the generation of variation. Annual Review of Phytopathology, 30:153-171, 190-200; 279 ref

Brasier CM, Hansen EM, 1992. Evolutionary biology of Phytophthora. Part II: phylogeny, speciation and population structure. Annual Review of Phytopathology, 30:173-200; 279 ref

Brooks F, 2002. List of Plant Diseases in American Samoa 2002. Land Grant Technical Report No. 44. Pago Pago, American Samoa: American Samoa Community College Land Grant Program

Cárdenas ME, Medina E, Tabima J, Vargas A, Lopera C, Bernal A, Restrepo S, 2011. First report of Phytophthora infestans causing late blight on Solanum viarum in Colombia. Plant Disease, 95(7):875. http://apsjournals.apsnet.org/loi/pdis

CMI, 1982. Distribution Maps of Plant Diseases, No. 109, Edition 5. Wallingford, UK: CAB International

Coca Morante M, 2016. Disease note: first records of potato late blight caused by Phytophthora infestans in Bolivia. Journal of Plant Pathology and Microbiology, 7(8):374. http://www.omicsonline.org/open-access/disease-note-first-records-of-potato-late-blight-caused-by-phytophthora-infestans-in-bolivia-2157-7471-1000374.pdf

Connell TR, Koenig JP, Stevenson WR, Kelling KA, Curwen D, Wyman JA, Binning LK, 1991. An integrated systems approach to potato crop management. Journal of Production Agriculture, 4:453-460

Cox AE, Large EC, 1960. Potato late blight epidemics throughout the world. Washington DC, USA: US Government Printing Office

Crosier W, 1934. Studies in the biology of Phytophthora infestans (Mont) de Bary. Cornell University Agricultural Experiment Station, Ithaca, NY(Memoir 155)

Cupsa I, Ignatescu I, Vogel E, 1983. An epidemic of potato late blight in 1982, and measures taken to prevent it in 1983. Productia Vegetala, Horticultura, 32(5): 22-26

Daggett, S. S., Götz, E., Therrien, C. D., 1993. Phenotypic changes in populations of Phytophthora infestans from Eastern Germany. Phytopathology, 83(3), 319-323. doi: 10.1094/Phyto-83-319

Dangi S, Rosenzweig N, Steere L, Kirk WW, 2016. First report of late blight caused by Phytophthora infestans clonal lineage US-23 variant on potato in Michigan, USA. Plant Disease, 100(8):1797. http://apsjournals.apsnet.org/loi/pdis

Dar GM, Dar GH, Baba RA, Munshi NA, 2004. Causes and management of tomato fruit rots in Kashmir. Applied Biological Research, 6(1/2):22-26. http://www.indianjournals.com

Day JP, Wattier RAM, Shaw DS, Shattock RC, 2004. Phenotypic and genotypic diversity in Phytophthora infestans on potato in Great Britain, 1995-98. Plant Pathology, 53(3):303-315. http://www.blackwellpublishing.com/ppa

De BK, Basu A, 2002. Three decades study on monitoring of late blight disease of potato in the plains of West Bengal. Environment and Ecology, 20(1):216-218

de Weille GA, 1964. Forecasting crop infection by the potato blight fungus. Meded. Verh. K. Ned. Met. Inst., 82:1-144

Deahl KL, Perez FM, Thompson JM, Fleming-Archibald C, Thompson S, Collier R, Kildea S, Cooke LR, 2009. Characterization of Phytophthora infestans isolates from Jersey, Channel Islands. Potato Research, 52(4):341-354. http://springerlink.com/content/y212486611636282/?p=18f0456c51864a6e9710bab1bdefe9dc&pi=6

Dick MW, 1995a. Sexual reproduction in the Peronosporomycetes (Chromistan fungi). Canadian Journal of Botany, 73(Supplement 1):5712-5724

Drenth A, Janssen EM, Govers F, 1995. Formation and survival of oospores of Phytophthora infestans under natural conditions. Plant Pathology, 44(1):86-94

Erselius LJ, Hohl HR, Ord=nez ME, Oyarzun PJ, Jarrin F, Velasco A, Ramon MP, Forbes GA, 1999. Genetic diversity among isolates of Phytophthora infestans from various hosts in Ecuador. Impact on a changing world. International Potato Center Program Report 1997-1998., 39-48; 35 ref

Erselius LJ, Vega-Sßnchez ME, Forbes GA, 2000. Stability in population of Phytophthora infestans attacking tomato in Ecuador demonstrated by cellulose acetate assessment of glucose-6-phosphate isomerase. Plant Disease, 84(3):325-327; 17 ref

Erwin DC, Ribeiro OK, 1996. Phytophthora Diseases Worldwide. St Paul, Minnesota, USA: American Phytopathological Society Press

FAO/CIP, 1995. Potatoes, Rome: FAO-International Potato Center

Filippov AV, Kuznetsova MA, Iakusheva OI, Rogozhin AN, Statsyuk NV, Demedova VN, Borovsky KV, 2019. Minimization of fungicidal applications against potato late blight in the North Caucasian Region: use of "Agrodozor" system. In: International scientific and practical conference "AgroSMART - Smart solutions for agriculture" : KnE Life Sciences. 884-892. doi: 10.18502/kls.v4i14.5686

Fontem DA, Aighewi B, 1993. Effect of fungicides on late blight control and yield loss of potato in the western highlands of Cameroon. International Journal of Pest Management, 39(2):152-155

Fry WE, Bruck RI, Mundt CC, 1979. Retardation of potato late blight epidemics by fungicides with eradicant and protectant properties. Plant Disease Reporter, 63(11):970-974

Fry WE, Goodwin SB, 1995. Recent migrations of Phytophthora infestans. In: Dowley LJ, Bannon E, Cooke LR, Keane T, O'Sullivan E, eds. Phytophthora infestans 150. Dublin, Irish Republic: Boole Press Ltd., 89-95

Fry WE, Goodwin SB, Dyer AT, Matuszak JM, Drenth A, Tooley PW, Sujkowski LS, Koh YJ, Cohen BA, Spielman LJ, Deahl KL, Inglis DA, Sandlan KP, 1993. Historical and recent migrations of Phytophthora infestans: chronology, pathways, and implications. Plant Disease, 77(7):653-661

Gevens AJ, Seidl AC, 2013. First report of late blight caused by Phytophthora infestans clonal lineage US-22 on tomato and potato in Wisconsin. Plant Disease, 97(3):423. http://apsjournals.apsnet.org/loi/pdis

Gevens AJ, Seidl AC, 2013. First report of late blight caused by Phytophthora infestans clonal lineage US-23 on tomato and potato in Wisconsin, United States. Plant Disease, 97(6):839. http://apsjournals.apsnet.org/loi/pdis

Goodwin SB, Cohen BA, Deahl KL, Fry WE, 1994. Migration from northern Mexico as the probable cause of recent genetic changes in populations of Phytophthora infestans in the United States and Canada. Phytopathology, 84(6):553-558

Goodwin SB, Cohen BA, Fry WE, 1994b. Panglobal distribution of a single clonal lineage of the Irish potato famine fungus. Proceedings National Academy of Sciences USA, 91:11591-11595

Goodwin SB, Schneider RE, Fry WE, 1995. Use of cellulose-acetate electrophoresis for rapid identification of allozyme genotypes of Phytophthora infestans. Plant Disease, 79(11):1181-1185; 20 ref

Goodwin SB, Sujkowski LS, Dyer AT, Fry BA, Fry WE, 1995. Direct detection of gene flow and probable sexual reproduction of Phytophthora infestans in northern North America. Phytopathology, 85(4):473-479

Goodwin, S. B., Legard, D. E., Smart, C. D., Levy, M., Fry, W. E., 1999. Gene flow analysis of molecular markers confirms that Phytophthora mirabilis and P. infestans are separate species. Mycologia, 91(5), 796-810. doi: 10.2307/3761533

Hermansen, A., Hannukkala, A., Naerstad, R. H., Brurberg, M. B., 2000. Variation in populations of Phytophthora infestans in Finland and Norway: mating type, metalaxyl resistance and virulence phenotype. Plant Pathology, 49(1), 11-22. doi: 10.1046/j.1365-3059.2000.00426.x

Higiro J, 1995. Potato production in Burundi: constraints and research. Breeding for disease resistance with emphasis on durability. Proceedings of a regional workshop for eastern, central and southern Africa, held at Njoro, Kenya, October 2-6, 1994 [edited by Danial, D. L.] Wageningen, Netherlands; Landbouwuniversiteit Wageningen (Wageningen Agricultural University), 117-118

Hijmans RJ, Forbes GA, Walker TS, 2000. Estimating the global severity of potato late blight with a GIS-linked disease forecaster. In: Impact on a changing world. International Potato Center Program Report, 1997-1998. Lima, Peru: Centro Internacional de la Papa, 83-90

Hohl HR, Iselin K, 1984. Strains of Phytophthora infestans from Switzerland with A2 mating type behaviour. Transactions of the British Mycological Society, 83(3):529-530

Hossain M, Dey TK, Hossain MI, Begum SN, Kadian MS, 2009. Research experience on potato late blight disease management in Bangladesh. Acta Horticulturae [Proceedings of the III International Late Blight Conference, Beijing, China, 3-6 April 2008.], No.834:175-186. http://www.actahort.org/books/834/834_19.htm

Ilhe BM, Warade SD, 2007. Management of fungal disease complex of tomato (cv. Rajashree) during rainy season. Journal of Maharashtra Agricultural Universities, 32(2):252-254

Inglis DA, Powelson ML, Dorrance AE, 1999. Effect of registered potato seed piece fungicides on tuber-borne Phytophthora infestans. Plant Disease, 83(3):229-234; 17 ref

Jhilmil Gupta, Singh PH, Devendra Kumar, Ela Atheaya, Singh BP, 2001. Status of mating types and metalaxyl resistance in Phytophthora infestans population during 2000-2001. Journal of the Indian Potato Association [National symposium on sustainability of potato revolution in India, Shimla, India, 31 July 2001.], 28(1):74-75

Jin FangLun, Xu Qiong, Han ChengMing, 2008. Occurrence regulation of tomato late blight and its control technique in Northern Guizhou. Guizhou Agricultural Sciences, No.6:72-74

Johnson DA, Cummings TF, Hamm PB, Rowe RC, Miller JS, Thornton RE, Pelter GQ, Sorensen EJ, 1997. Potato late blight in the Columbia basin: an economic analysis of the 1995 epidemic. Plant Disease, 81(1):103-106; 19 ref

Jorgensen LN, Jensen PK, Holm S, Mikkelsen G, Kristensen IS, Orum JE, 1999. Estimated crop losses and crop rotations in a scenario without pesticides. In: Proceedings of the 16th Danish Plant Protection Conference. DJR Rapport, Markburg. Tjiele, Denmark: Danmarks JordbrugsForskning, 7-26

Kalyebara RM, 1994. Some indicators for monitoring and evaluation of the impact of Irish potato research and extension in Uganda: Results of a baseline study. Kampala, Uganda: PRAPACE

Khan BA, Haq I, Iftikhar S, Aslam M, 1985. Occurrence of late blight of potato in Pakistan. Pakistan Journal of Botany, 17(1):163

Knapova, G., Gisi, U., 2002. Phenotypic and genotypic structure of Phytophthora infestans populations on potato and tomato in France and Switzerland. Plant Pathology, 51(5), 641-653. doi: 10.1046/j.1365-3059.2002.00750.x

Krause RA, Massie LB, Hyre RA, 1975. Blitecast: a computerized forecast of potato late blight. Plant Disease Reporter, 59(2):95-98

Kuznetsova, M. A., Kozlovsky, B. E., Beketova, M. P., Sokolova, E. A., Malyuchenko, O. P., Alekseev, Ya. I., Rogozina, E. V., Khavkin, E. E., 2016. Phytopathological and molecular characteristics of Phytophthora infestans isolates collected on resistant and susceptible potato genotypes. Mikologiya i Fitopatologiya, 50(3), 175-184.

Kuznetsova, M. A., Statsyuk, N. V., Kozlovsky, B. E. (et al), 2013. Current status of the Phytophthora infestans population and protection of potato from late blight of potato. Zashchita i Karantin Rastenii, (No.7), 12-15. http://www.z-i-k-r.ru

Lakra BS, 2004. Health status of potato crop in Haryana - an overall view. Haryana Journal of Horticultural Sciences, 33(3/4):294-296

Lebreton L, Lucas JM, Andrivon D, 1999. Aggressiveness and competitive fitness of Phytophthora infestans isolates collected from potato and tomato in France. Phytopathology, 89(8):679-686; 28 ref

Legard DE, Lee TY, Fry WE, 1995. Pathogenic specialization in Phytophthora infestans: aggressiveness on tomato. Phytopathology, 85(11):1356-1361; 30 ref

López Orona CA, Martínez AR, Arteaga TT, García HG, Palmero D, Ruiz CA, Peñuelas CG, 2013. First report of homothallic isolates of Phytophthora infestans in commercial potato crops (Solanum tuberosum) in the Toluca Valley, Mexico. Plant Disease, 97(8):1112. http://apsjournals.apsnet.org/loi/pdis

Malyuga AA, Konyaeva NM, Enina NN, Orlova EA, Safonova AD, 2003. Cultivars adopted for different zones resistant to pathogens. Zashchita i Karantin Rastenii, No.10:29-31

Metreveli VN, Ordzhonikidze EK, 2002. Sunmite and Euparen against rusty mite and blight on tomatoes. Zashchita i Karantin Rastenii, No.11:22

Mijatovic MM, Zdravkovic J, Markovic Z, 2007. Reaction of some tomato cultivars and hybrids to late blight (P. infestans Mont. de Bary). Acta Horticulturae [Proceedings of the Third Balkan Symposium on Vegetables and Potatoes, Bursa, Turkey, 6-10 September 2004.], No.729:463-466. http://www.actahort.org

Minogue KP, Fry WE, 1981. Effect of temperature, relative humidity, and rehydration rate on germination of dried sporangia of Phytophthora infestans. Phytopathology, 71(11):1181-1184

Ordonez ME, Hohl HR, Velasco JA, Ramon MP, Oyarzun PJ, Smart CD, Fry WE, Forbes GA, Erselius LJ, 2000. A novel population of Phytophthora, similar to P. infestans, attacks wild Solanum species in Ecuador. Phytopathology, 90(2):197-202; 28 ref

Ortiz O, Winters P, Fano H, Thiele G, Guaman S, Torres R, Barrera V, Unda J, Hakiza J, 1999. Understanding Farmers' responses to late blight: Evidence from Peru, Bolivia, Ecuador, and Uganda. In: Center IP, eds. Impact on a changing world: Program report, 1997-98. Lima, Peru: International Potato Center, 101-109

Oyarzun PJ, Pozo A, Ordonez ME, Doucett K, Forbes GA, 1998. Host specificity of Phytophthora infestans on tomato and potato in Ecuador. Phytopathology, 88(3):265-271; 31 ref

Phukan SN, 2008. Studies on the distribution pattern of major diseases of potato and growth characteristics of associated causal organisms in the district of Lakhimpur, Assam. Advances in Plant Sciences, 21(2):407-409

Piekarczyk K, Babilas W, 1986. Occurrence of the most serious diseases and pests of potato in Poland in 1981. Biuletyn Instytutu Ochrony Roslin, 101-134

Pietkiewicz JB, 1991. Potato production and protection in Poland in the 1990s. Bulletin OEPP, 21(1):1-7

Pliakhnevich M, Ivaniuk V, 2008. Aggressiveness and metalaxyl sensitivity of Phytophthora infestans strains in Belarus. Zemdirbyste (Agriculture), 95(3):379-387. http://www.lzi.lt

Powelson ML, Inglis DA, 1999. Foliar fungicides as protective seed piece treatments for management of late blight of potatoes. Plant Disease, 83(3):265-268; 17 ref

Rao ANS, Veeresh GK, 1989. Estimation of yield loss due to late blight in rainfed potato. Current Research - University of Agricultural Sciences (Bangalore), 18(11):157-158

Reed HS, 1912. Does Phytophthora infestans cause tomato blight? Phytopathology, 11:250-252

Reis A, Ribeiro FHS, Mizubuti ESG, 2006. Characterization of Phytophthora infestans isolates from Distrito Federal and Goiás, Brazil. (Caracterização de isolados de Phytophthora infestans do Distrito Federal e de Goiás.) Fitopatologia Brasileira, 31(3):270-276. http://www.scielo.br/scielo.php?script=sci_pdf&pid=S0100-41582006000300005&lng=en&nrm=iso&tlng=pt

Rivera-Pena A, Molina-Galan J, 1989. Wild tuber-bearing species of Solanum and incidence of Phytophthora infestans (Mont.) de Bary on the western slopes of the volcano Nevado de Toluca. 1. Solanum species. Potato Research, 32:181-195

Rubin E, Baider A, Cohen Y, 2001. Phytophthora infestans produces oospores in fruits and seeds of tomato. Phytopathology, 91(11):1074-1080; 32 ref

Schotman CYL, 1989. Plant pests of quarantine importance to the Caribbean. RLAC-PROVEG, No. 21:80 pp

Shantanu Kumar, Uma Sah, Deka C, Baishya LK, Pandey NK, Singh PH, Pandey SK, 2008. Farmer participatory research for design and delivery of situation specific potato production technology in Meghalya. Potato Journal , 35(1/2):78-84. http://www.indianjournals.com/ijor.aspx?target=ijor:pj&type=home

Shrestha SK, Karmacharya BL, Rana RB, 1986. Potato diseases and their economic importance in Bhutan. FAO Plant Protection Bulletin, 34(3):157-159

Spielman LJ, Drenth A, Davidse LC, Sujkowski LJ, Gu W, Tooley PW, Fry WE, 1991. A second world-wide migration and population displacement of Phytophthora infestans? Plant Pathology, 40(3):422-430

Stamps DJ, 1985. Phytophthora infestans. CMI Descriptions of Pathogenic Fungi and Bacteria, No. 838. Wallingford, UK: CAB International

Sujkowski LS, Goodwin SB, Dyer AT, Fry WE, 1994. Increased genotypic diversity via migration and possible occurrence of sexual reproduction of Phytophthora infestans in Poland. Phytopathology, 84(2):201-207

Thurston HD, 1994. Andean potato culture: 5,000 years of experience with sustainable agriculture. In: G. W. Zehnder MLP, R. K. Jansson, K. V. Raman, eds. Advances in potato pest biology and management. St. Paul, USA: APS Press, 6-13

Trotus E, Naie M, 2008. Data on the knowledge of injurious organisms in hemp crops from the Central Moldavia. Cercetari Agronomice în Moldova, 41(3):51-57

Trout CL, Ristaino JB, Madritch M, Wangsomboondee T, 1997. Rapid detection of Phytophthora infestans in late blight-infected potato and tomato using PCR. Plant Disease, 81(9):1042-1048; 29 ref

Turkensteen LJ, 1973. Partial resistance of tomatoes against Phytophthora infestans the late blight fungus. Inst. Plantenziektekd. Onderz. Wageningen, Nederland, Meded., 633:1-88

Turkensteen LJ, 1978. Phytophthora infestans: three new hosts and a specialized form causing a foliar blight of Solanum muricatum in Peru. Plant Disease Reporter, 62(9):829

Van der Zaag DE, 1956. Overwintering and epidemiology of Phytophthora infestans, and some new possibilities of control. Tijdschrift over Plantenziekten, 62:129-140

Van Everdingen E, 1926. Het verband tusschen de weergesteldheid en de aardappel zeikte (Phytophthora infestans). Tijdschrift over Plantenziekten, 32:129

Vargas, A. M., Correa, A., Lozano, D. C., González, A., Bernal, A. J., Restrepo, S., Jiménez, P., 2007. First report of late blight caused by Phytophthora infestans on Cape gooseberry (Physalis peruviana) in Colombia. Plant Disease, 91(4), 464. doi: 10.1094/PDIS-91-4-0464B

Vartanian VG, Endo RM, 1985. Overwintering hosts, compatibility types, and races of Phytophthora infestans on tomato in southern California. Plant Disease, 69(6):516-519

Vartanian VG, Endo RM, 1985. Survival of Phytophthora infestans in seeds extracted from infected tomato fruits. Phytopathology, 75(3):375-378

Vega-Sßnchez ME, Erselius LJ, Rodriguez AM, Bastidas O, Hohl HR, Ojiambo PS, Mukalazi J, Vermeulen T, Fry WE, Forbes GA, 2000. Host adaptation to potato and tomato within the US-1 clonal lineage of Phytophthora infestans in Uganda and Kenya. Plant Pathology, 49(5):531-539; 33 ref

Vossen, E. van der, Sikkema, A., Hekkert, B. te L., Gros, J., Stevens, P., Muskens, M., Wouters, D., Pereira, A., Stiekema, W., Allefs, S., 2003. An ancient R gene from the wild potato species Solanum bulbocastanum confers broad-spectrum resistance to Phytophthora infestans in cultivated potato and tomato. Plant Journal, 36(6), 867-882. doi: 10.1046/j.1365-313X.2003.01934.x

Wamser AF, Becker WF, Santos JPdos, Mueller S, 2008. Influence of the training systems of tomato plants on the incidence of diseases and insect-pests. (Influência do sistema de condução do tomateiro sobre a incidência de doenças e insetos-praga.) Horticultura Brasileira, 26(2):180-185. http://www.scielo.br/scielo.php/script_sci_serial/pid_0102-0536/lng_en/nrm_iso

Wharton PS, Nolte P, Kirk WW, Dangi S, Gevens AJ, 2015. First report of late blight caused by Phytophthora infestans clonal lineage US-23 on potato in Idaho. Plant Disease, 99(3):417. http://apsjournals.apsnet.org/loi/pdis

Ye GuangJi, Sun HaiHong, Zhou Yun, Yang YongZhi, Wang Jian, 2008. Composition and distribution of physiological race of Phytophthora infestans in the Haidong region of Qinghai province. Acta Phytopathologica Sinica, 38(5):553-556. http://zwblxb.periodicals.net.cn/default.html

Yu WenGui, Zou ChaYing, Zhao TongMin, Chen ZhiYi, Xue LinBao, Fan XueZhen, 2007. Identification of physiological races of Phytophthora infestans from tomato in Jiangsu Province and screening of resistance resource of tomato. Jiangsu Journal of Agricultural Sciences, 23(6):618-621. http://www.jaas.ac.cn

Zarzycka H, Sujkowski LS, 2000. A comparison of foliage resistance to Phytophthora infestans of some Dutch and Polish potato cultivars. Phytopathologia Polonica, No. 20:15-24

Zeng HuiCai, Ho, H. H., Zheng FuyCong, 2009. A survey of Phytophthora species on Hainan Island of South China. Journal of Phytopathology, 157(1), 33-39. doi: 10.1111/j.1439-0434.2008.01441.x

Zhang ZhiMing, Zhu JieHua, Song BoFu, Li YuQin, Tian ShiMin, Jiang HuShan, 2001. Further investigations on A2 mating type of Phytophthora infestans in China. Journal of Hebei Agricultural University, 24(2):32-37

Zhang ZiJun, Zou QingDao, Guan TianShu (et al), 2007. Identification of physiological races and disease resistance of Phytophtora infestans on tomato in partial Liaoning Province. China Vegetables, No.8:24-26

Zhu GuiNing, Huang FuXin, Feng LanXiang, Qin BiXia, Yang YuHong, Chen YongHui, Lu XiuHong, 2008. Sensitivities of Phytophthora infestans to metalaxyl, cymoxanil, and dimethomorph. Agricultural Sciences in China, 7(7):831-840. http://www.sciencedirect.com/science/journal/16712927

Zhu XiaoQiong, Che XingBi, Guo LiYun, Wang YingHua, 2004. Mating type of Phytophthora infestans from six provinces (cities) in China and their sensitivity to several fungicides. Plant Protection, 30(4):20-23

Zhu XiaoQiong, Wang YingHua, Guo LiYun, 2006. Genetic diversity revealed by RAPD analysis among isolates of Phytophthora infestans from different locations in China. Acta Phytopathologica Sinica, 36(3):249-258

Distribution References

Adler N E, Chacón G, Flier W G, Forbes G A, 2002. The Andean fruit crop, pear melon (Solanum muricatum) is a common host for A1 and A2 strains of Phytophthora infestans in Ecuador. Plant Pathology. 51 (6), 802. DOI:10.1046/j.1365-3059.2002.00772.x

Adler N E, Erselius L J, Chacón M G, Flier W G, Ordoñez M E, Kroon L P N M, Forbes G A, 2004. Genetic diversity of Phytophthora infestans sensu lato in Ecuador provides new insight into the origin of this important plant pathogen. Phytopathology. 94 (2), 154-162. DOI:10.1094/PHYTO.2004.94.2.154

Andersson B, Johansson M, Jönsson B, 2003. First report of Solanum physalifolium as a host plant for Phytophthora infestans in Sweden. Plant Disease. 87 (12), 1538. DOI:10.1094/PDIS.2003.87.12.1538B

Andrivon D, Béasse C, Laurent C, 1994. Characterization of isolates of Phytophthora infestans collected in northwestern France from 1988 to 1992. Plant Pathology. 43 (3), 471-478. DOI:10.1111/j.1365-3059.1994.tb01580.x

Andrivon D, Pilet F, Montarry J, Hafidi M, Corbière R, Achbani E, Pellé R, Ellissèche D, 2007. Adaptation of Phytophthora infestans to partial resistance in potato: evidence from French and Moroccan populations. Phytopathology. 97 (3), 338-343. DOI:10.1094/PHYTO-97-3-0338

Arora R K, 2009. Late blight: an increasing threat to seed potato production in the north-western plains of India. Acta Horticulturae. 201-204. http://www.actahort.org/books/834/834_22.htm

Arti Shukla, Gupta S K, Sharma H R, 2013. Occurrence of late blight in cherry tomato grown under protected conditions in Himachal Pradesh. Plant Disease Research. 28 (2), 205-206. http://insopp.org.in/

Bekele Kassa, Sommartya T, 2006. Effect of intercropping on potato late blight, Phytophthora infestans (Mont.) de Bary development and potato tuber yield in Ethiopia. Kasetsart Journal, Natural Sciences. 40 (4), 914-924.

Brooks F, 2002. List of Plant Diseases in American Samoa 2002. In: Land Grant Technical Report No. 44, Pago Pago, American Samoa, American Samoa Community College Land Grant Program.

CABI, Undated. Compendium record. Wallingford, UK: CABI

CABI, Undated a. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI

CABI, Undated b. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI

Camele I, Marcone C, Cristinzio G, 2005. Detection and identification of Phytophthora species in Southern Italy by RFLP and sequence analysis of PCR-amplified nuclear ribosomal DNA. European Journal of Plant Pathology. 113 (1), 1-14. DOI:10.1007/s10658-005-8915-1

Camele I, Marcone C, Rana G L, 2005a. Detection and characterization of Phytophthora species infecting tomato in Southern Italy by DNA-based methods. Acta Horticulturae. 373-378. http://www.actahort.org

Cárdenas M E, Medina E, Tabima J, Vargas A, Lopera C, Bernal A, Restrepo S, 2011. First report of Phytophthora infestans causing late blight on Solanum viarum in Colombia. Plant Disease. 95 (7), 875. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-11-10-0853

Carter D A, Archer S A, Buck K W, Shaw D S, Shattock R C, 1990. Restriction fragment length polymorphisms of mitochondrial DNA of Phytophthora infestans. Mycological Research. 94 (8), 1123-1128. DOI:10.1016/S0953-7562(09)81344-0

Carter G A, Smith R M, Brent K J, 1982. Sensitivity to metalaxyl of Phytophthora infestans populations in potato crops in south-west England in 1980 and 1981. Annals of Applied Biology. 100 (3), 433-441. DOI:10.1111/j.1744-7348.1982.tb01410.x

Casa-Coila V H, Lehner M S, Hora Júnior B T, Reis A, Nazareno N R X, Mizubuti E S G, Gomes C B, 2017. First report of Phytophthora infestans self-fertile genotypes in southern Brazil. Plant Disease. 101 (9), 1682. DOI:10.1094/PDIS-02-17-0215-PDN

Coca Morante M, 2016. Disease note: first records of potato late blight caused by Phytophthora infestans in Bolivia. Journal of Plant Pathology and Microbiology. 7 (8), 374. http://www.omicsonline.org/open-access/disease-note-first-records-of-potato-late-blight-caused-by-phytophthora-infestans-in-bolivia-2157-7471-1000374.pdf

Cohen Y, 2002. Populations of Phytophthora infestans in Israel underwent three major genetic changes during 1983 to 2000. Phytopathology. 92 (3), 300-307. DOI:10.1094/PHYTO.2002.92.3.300

Cooke D E L, Randall E, Sullivan L, Lees A K, 2018. The origins and implications of a novel population of Phytophthora infestans on potato crops in Scotland. In: The Dundee Conference. Crop Production in Northern Britain 2018, Dundee, UK, 27-28 February 2018 [The Dundee Conference. Crop Production in Northern Britain 2018, Dundee, UK, 27-28 February 2018.], Dundee, UK: The Association for Crop Protection in Northern Britain. 203-208.

Cooke D E L, Young V, Birch P R J, Toth R, Gourlay F, Day J P, Carnegie S F, Duncan J M, 2003. Phenotypic and genotypic diversity of Phytophthora infestans populations in Scotland (1995-97). Plant Pathology. 52 (2), 181-192. DOI:10.1046/j.1365-3059.2003.00817.x

Daggett S S, Götz E, Therrien C D, 1993. Phenotypic changes in populations of Phytophthora infestans from Eastern Germany. Phytopathology. 83 (3), 319-323. DOI:10.1094/Phyto-83-319

Dangi S, Rosenzweig N, Steere L, Kirk W W, 2016. First report of late blight caused by Phytophthora infestans clonal lineage US-23 variant on potato in Michigan, USA. Plant Disease. 100 (8), 1797. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-02-16-0228-PDN

Dar G M, Dar G H, Baba R A, Munshi N A, 2004. Causes and management of tomato fruit rots in Kashmir. Applied Biological Research. 6 (1/2), 22-26. http://www.indianjournals.com

Day J P, Wattier R A M, Shaw D S, Shattock R C, 2004. Phenotypic and genotypic diversity in Phytophthora infestans on potato in Great Britain, 1995-98. Plant Pathology. 53 (3), 303-315. http://www.blackwellpublishing.com/ppa DOI:10.1111/j.0032-0862.2004.01004.x

De B K, Basu A, 2002. Three decades study on monitoring of late blight disease of potato in the plains of West Bengal. Environment and Ecology. 20 (1), 216-218.

Deahl K L, Fravel D R, 2003. Occurrence of leaf blight on Petunia caused by Phytophthora infestans in Maryland. Plant Disease. 87 (8), 1004. DOI:10.1094/PDIS.2003.87.8.1004A

Deahl K L, Jones R W, Black L L, Wang T C, Cooke L R, 2008. First report of the A2 mating type of Phytophthora infestans on tomato crops in Taiwan, Republic of China. Plant Disease. 92 (6), 978. DOI:10.1094/PDIS-92-6-0978A

Deahl K L, Jones R, Wanner L A, 2005. Late blight caused by Phytophthora infestans on Solanum sarrachoides in Northeastern Maine. Plant Disease. 89 (4), 435. DOI:10.1094/PD-89-0435A

Deahl K L, Perez F M, Thompson J M, Fleming-Archibald C, Thompson S, Collier R, Kildea S, Cooke L R, 2009. Characterization of Phytophthora infestans isolates from Jersey, Channel Islands. Potato Research. 52 (4), 341-354. http://springerlink.com/content/y212486611636282/?p=18f0456c51864a6e9710bab1bdefe9dc&pi=6 DOI:10.1007/s11540-009-9138-1

Elansky S N, Pobedinskaya M A, Mita E D, Plyakhnevich M P, 2012. Resistance of potato and tomato late blight pathogen to fungicides. Mikologiya i Fitopatologiya. 46 (5), 340-344. http://www.nauka.nw.ru

Elansky S, Smirnov A, Dyakov Y, Dolgova A, Filippov A, Kozlovsky B, Kozlovskaya I, Russo P, Smart C, Fry W, 2001. Genotypic analysis of Russian isolates of Phytophthora infestans from the Moscow region, Siberia and Far East. Journal of Phytopathology. 149 (10), 605-611. DOI:10.1046/j.1439-0434.2001.00642.x

Fernández-Pavía S P, Grünwald N J, Fry W E, 2002. Formation of Phytophthora infestans oospores in nature on tubers in Central Mexico. Plant Disease. 86 (1), 73. DOI:10.1094/PDIS.2002.86.1.73C

Fontem D A, Olanya O M, Njualem B F, 2004. Reaction of certain solanaceous and asteraceous plant species to inoculation with Phytophthora infestans in Cameroon. Journal of Phytopathology. 152 (6), 331-336. DOI:10.1111/j.1439-0434.2004.00850.x

Forbes G A, Escobar X C, Ayala C C, Revelo J, Ordoñez M E, Fry B A, Doucett K, Fry W E, 1997. Population genetic structure of Phytophthora infestans in Ecuador. Phytopathology. 87 (4), 375-380. DOI:10.1094/PHYTO.1997.87.4.375

Garay-Serrano E, Fernández-Pavía S P, Rodríguez-Alvarado G, Flier W G, Rojas-Martínez R I, Goss E M, Grünwald N J, 2007. First report of haplotype I-b of Phytophthora infestans in central Mexico. Plant Disease. 91 (7), 909. DOI:10.1094/PDIS-91-7-0909B

Gavino P D, Fry W E, 2002. Diversity in and evidence for selection on the mitochondrial genome of Phytophthora infestans. Mycologia. 94 (5), 781-793. DOI:10.2307/3761693

Gevens A J, Seidl A C, 2013. First report of late blight caused by Phytophthora infestans clonal lineage US-22 on tomato and potato in Wisconsin. Plant Disease. 97 (3), 423. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-08-12-0807-PDN

Gevens A J, Seidl A C, 2013a. First report of late blight caused by Phytophthora infestans clonal lineage US-23 on tomato and potato in Wisconsin, United States. Plant Disease. 97 (6), 839. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-09-12-0821-PDN

Gevens A J, Seidl A C, 2013b. First report of late blight caused by Phytophthora infestans clonal lineage US-24 on potato (Solanum tuberosum) in Wisconsin. Plant Disease. 97 (1), 152-153. DOI:10.1094/PDIS-09-12-0825-PDN

Goodwin S B, Legard D E, Smart C D, Levy M, Fry W E, 1999. Gene flow analysis of molecular markers confirms that Phytophthora mirabilis and P. infestans are separate species. Mycologia. 91 (5), 796-810. DOI:10.2307/3761533

Goodwin S B, Sujkowski L S, Dyer A T, Fry B A, Fry W E, 1995. Direct detection of gene flow and probable sexual reproduction of Phytophthora infestans in northern North America. Phytopathology. 85 (4), 473-479. DOI:10.1094/Phyto-85-473

Hermansen A, Hannukkala A, Naerstad R H, Brurberg M B, 2000. Variation in populations of Phytophthora infestans in Finland and Norway: mating type, metalaxyl resistance and virulence phenotype. Plant Pathology. 49 (1), 11-22. DOI:10.1046/j.1365-3059.2000.00426.x

Hossain M, Dey T K, Hossain M I, Begum S N, Kadian M S, 2009. Research experience on potato late blight disease management in Bangladesh. Acta Horticulturae. 175-186. http://www.actahort.org/books/834/834_19.htm

Ilhe B M, Warade S D, 2007. Management of fungal disease complex of tomato (cv. Rajashree) during rainy season. Journal of Maharashtra Agricultural Universities. 32 (2), 252-254.

Ivanović M, Mijatović M, Zečević B, Niepold F, Ivanović M, 2007. Occurrence of new populations and mating types of Phytophthora infestans (Mont) de Bary in Serbia. Acta Horticulturae. 499-502. http://www.actahort.org

Jaimasit P, Prakob W, 2010. Characterization of Phytophthora infestans population in potato crops from Chiang Mai and Tak Provinces. International Journal of Agricultural Technology. 6 (1), 117-125. http://ijat-rmutto.com/pdf/Jan_v6_n1_10/13-108-IJAT2009_88F.pdf

Jaime-Garcia R, Orum T V, Felix-Gastelum R, Trinidad-Correa R, VanEtten H D, Nelson M R, 2001. Spatial analysis of Phytophthora infestans genotypes and late blight severity on tomato and potato in the Del Fuerte Valley using geostatistics and geographic information systems. Phytopathology. 91 (12), 1156-1165. DOI:10.1094/PHYTO.2001.91.12.1156

Jhilmil Gupta, Singh P H, Devendra Kumar, Ela Atheaya, Singh B P, 2001. Status of mating types and metalaxyl resistance in Phytophthora infestans population during 2000-2001. Journal of the Indian Potato Association. 28 (1), 74-75.

Jin FangLun, Xu Qiong, Han ChengMing, 2008. Occurrence regulation of tomato late blight and its control technique in Northern Guizhou. Guizhou Agricultural Sciences. 72-74.

Kawchuk L M, Howard R J, Peters R D, Al-Mughrabi K I, 2011. First report of Phytophthora infestans genotype US23 causing late blight in Canada. Plant Disease. 95 (7), 873. DOI:10.1094/PDIS-01-11-0054

Knapova G, Gisi U, 2002. Phenotypic and genotypic structure of Phytophthora infestans populations on potato and tomato in France and Switzerland. Plant Pathology. 51 (5), 641-653. DOI:10.1046/j.1365-3059.2002.00750.x

Koh Y J, Goodwin S B, Dyer A T, Cohen B A, Ogoshi A, Sato N, Fry W E, 1994. Migrations and displacements of Phytophthora infestans populations in east Asian countries. Phytopathology. 84 (9), 922-927. DOI:10.1094/Phyto-84-922

Kuznetsova M A, Kozlovsky B E, Beketova M P, Sokolova E A, Malyuchenko O P, Alekseev Ya I, Rogozina E V, Khavkin E E, 2016. Phytopathological and molecular characteristics of Phytophthora infestans isolates collected on resistant and susceptible potato genotypes. Mikologiya i Fitopatologiya. 50 (3), 175-184.

Lakra B S, 2004. Health status of potato crop in Haryana - an overall view. Haryana Journal of Horticultural Sciences. 33 (3/4), 294-296.

Lievens B, Hanssen I R M, Vanachter A C R C, Cammue B P A, Thomma B P H J, 2004. Root and foot rot on tomato caused by Phytophthora infestans detected in Belgium. Plant Disease. 88 (1), 86. DOI:10.1094/PDIS.2004.88.1.86A

López Orona C A, Martínez A R, Arteaga T T, García H G, Palmero D, Ruiz C A, Peñuelas C G, 2013. First report of homothallic isolates of Phytophthora infestans in commercial potato crops (Solanum tuberosum) in the Toluca Valley, Mexico. Plant Disease. 97 (8), 1112. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-10-12-0962-PDN

Malyuga A A, Konyaeva N M, Enina N N, Orlova E A, Safonova A D, 2003. Cultivars adopted for different zones resistant to pathogens. Zashchita i Karantin Rasteniĭ. 29-31.

Mazáková J, Táborsky V, Zouhar M, Ryšánek P, Hausvater E, Doležal P, 2006. Occurrence and distribution of mating types A1 and A2 of Phytophthora infestans (Mont.) de Bary in the Czech Republic. Plant Protection Science. 42 (2), 41-48. http://www.cazv.cz

McLeod A, Coertze S, 2006. First report of Phytophthora infestans on Petunia × hybrida in South Africa. Plant Disease. 90 (12), 1550. DOI:10.1094/PD-90-1550B

McLeod A, Denman S, Sadie A, Denner F D N, 2001. Characterization of South African isolates of Phytophthora infestans. Plant Disease. 85 (3), 287-291. DOI:10.1094/PDIS.2001.85.3.287

Metreveli V N, Ordzhonikidze Ė K, 2002. Sunmite and Euparen against rusty mite and blight on tomatoes. Zashchita i Karantin Rasteniĭ. 22.

Mijatović M M, Zdravković J, Marković Ž, 2007. Reaction of some tomato cultivars and hybrids to late blight (P. infestans Mont. de Bary). Acta Horticulturae. 463-466. http://www.actahort.org

Muradov P Z, Shirinova G F, Asgerli L X, Allahverdiyev E, Gasimov C F, 2019. Species composition of fungi causing diseases in agricultural plants in agrarian sector of Azerbaijan. Journal of Applied and Natural Science. 11 (4), 785-790. DOI:10.31018/jans.v11i4.2168

Olafsson S, Hermansen A, 2001. Outbreak of potato late blight and first report of mating type A2 and metalaxyl resistance of Phytophthora infestans in Iceland. Plant Disease. 85 (5), 559. DOI:10.1094/PDIS.2001.85.5.559B

Peerzada S H, Najar A G, Mushtaq Ahmad, Dar G H, Bhat K A, 2013. Studies on status of late blight disease (Phytophthora infestans (Mont) de Bary) of potato in Kashmir Valley. International Journal of Current Microbiology and Applied Sciences. 2 (10), 7-15. http://www.ijcmas.com/vol-2-10/S.H.%20Peerzada,%20et%20al.pdf

Phukan S N, 2008. Studies on the distribution pattern of major diseases of potato and growth characteristics of associated causal organisms in the district of Lakhimpur, Assam. Advances in Plant Sciences. 21 (2), 407-409.

Pliakhnevich M, Ivaniuk V, 2008. Aggressiveness and metalaxyl sensitivity of Phytophthora infestans strains in Belarus. Žemdirbystė (Agriculture). 95 (3), 379-387. http://www.lzi.lt

Rashtra Vardhana, 2017. Plant's diseases of district Ghaziabad and adjacent areas. Plant Archives. 17 (1), 727-732. http://www.plantarchives.org/PDF%2017-1/727-732%20(3511).pdf

Reis A, Ribeiro F H S, Mizubuti E S G, 2006. Characterization of Phytophthora infestans isolates from Distrito Federal and Goiás, Brazil. (Caracterização de isolados de Phytophthora infestans do Distrito Federal e de Goiás.). Fitopatologia Brasileira. 31 (3), 270-276. http://www.scielo.br/scielo.php?script=sci_pdf&pid=S0100-41582006000300005&lng=en&nrm=iso&tlng=pt DOI:10.1590/S0100-41582006000300005

Schotman C Y L, 1989. Plant pests of quarantine importance to the Caribbean. In: RLAC-PROVEG, 80 pp.

Sedegui M, Carroll R B, Morehart A L, Evans T A, Kim S H, Lakhdar R, Arifi A, 2000. Genetic structure of the Phytophthora infestans population in Morocco. Plant Disease. 84 (2), 173-176. DOI:10.1094/PDIS.2000.84.2.173

Segura J M, Cara M de, Santos M, Tello J, 2007. Phytophthora infestans mating types on tomato (Solanum lycopersicum) in Southern Spain. Plant Disease. 91 (1), 109. DOI:10.1094/PD-91-0109B

Shantanu Kumar, Uma Sah, Deka C, Baishya L K, Pandey N K, Singh P H, Pandey S K, 2008. Farmer participatory research for design and delivery of situation specific potato production technology in Meghalya. Potato Journal. 35 (1/2), 78-84. http://www.indianjournals.com/ijor.aspx?target=ijor:pj&type=home

Shrestha G, Prajapati S, Mahato B N, 2014. Plant diseases and their management practices in commercial organic and conventional vegetable farms in Kathmandu valley. Nepalese Journal of Agricultural Sciences. 129-141. http://hicast.edu.np/file/file_down/pdf/pdf11/hx1JAeNJAS_2014_12.pdf

Tantius P H, Fyfe A M, Shaw D S, Shattock R C, 1986. Occurrence of the A2 mating type and self-fertile isolatesof Phytophthora infestans in England and Wales. 35 (4), 578 - 581. DOI:10.1111/j.1365-3059.1986.tb02057.x

Tosun N, Yıldırım A, Turkusay H, Tanyolac B, 2007. Genetic variation among Phytophthora infestans (tomato blight) isolates from western Turkey revealed by inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) markers. Pakistan Journal of Botany. 39 (3), 897-902. http://www.pjbot.org

Trotuș E, Naie M, 2008. Data on the knowledge of injurious organisms in hemp crops from the Central Moldavia. Cercetări Agronomice în Moldova. 41 (3), 51-57.

UK, CAB International, 1982. Phytophthora infestans. [Distribution map]. In: Distribution Maps of Plant Diseases, Wallingford, UK: CAB International. Map 109. DOI:10.1079/DMPD/20056500109

Vargas A M, Correa A, Lozano D C, González A, Bernal A J, Restrepo S, Jiménez P, 2007. First report of late blight caused by Phytophthora infestans on Cape gooseberry (Physalis peruviana) in Colombia. Plant Disease. 91 (4), 464. DOI:10.1094/PDIS-91-4-0464B

Vargas A M, Quesada Ocampo L M, Céspedes M C, Carreño N, González A, Rojas A, Paola Zuluaga A, Myers K, Fry W E, Jiménez P, Bernal A J, Restrepo S, 2009. Characterization of Phytophthora infestans populations in Colombia: first report of the A2 mating type. Phytopathology. 99 (1), 82-88. DOI:10.1094/PHYTO-99-1-0082

Vossen E van der, Sikkema A, Hekkert B te L, Gros J, Stevens P, Muskens M, Wouters D, Pereira A, Stiekema W, Allefs S, 2003. An ancient R gene from the wild potato species Solanum bulbocastanum confers broad-spectrum resistance to Phytophthora infestans in cultivated potato and tomato. Plant Journal. 36 (6), 867-882. DOI:10.1046/j.1365-313X.2003.01934.x

Wamser A F, Becker W F, Santos J P dos, Mueller S, 2008. Influence of the training systems of tomato plants on the incidence of diseases and insect-pests. (Influência do sistema de condução do tomateiro sobre a incidência de doenças e insetos-praga.). Horticultura Brasileira. 26 (2), 180-185. http://www.scielo.br/scielo.php/script_sci_serial/pid_0102-0536/lng_en/nrm_iso DOI:10.1590/S0102-05362008000200010

Wharton P S, Nolte P, Kirk W W, Dangi S, Gevens A J, 2015. First report of late blight caused by Phytophthora infestans clonal lineage US-23 on potato in Idaho. Plant Disease. 99 (3), 417. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-02-14-0196-PDN

Widmark A K, Andersson B, Cassel-Lundhagen A, Sandström M, Yuen J E, 2007. Phytophthora infestans in a single field in southwest Sweden early in spring: symptoms, spatial distribution and genotypic variation. Plant Pathology. 56 (4), 573-579. DOI:10.1111/j.1365-3059.2007.01618.x

Wijekoon C P, Peters R D, Al-Mughrabi K I, Kawchuk L M, 2014. First report of late blight caused by Phytophthora infestans clonal lineage US-23 on tomato and potato in Atlantic Canada. Plant Disease. 98 (3), 426. DOI:10.1094/PDIS-08-13-0807-PDN

Winton L M, Leiner R H, Krohn A L, Deahl K L, 2007. Occurrence of late blight caused by Phytophthora infestans on potato and tomato in Alaska. Plant Disease. 91 (5), 634. DOI:10.1094/PDIS-91-5-0634A

Ye GuangJi, Sun HaiHong, Zhou Yun, Yang YongZhi, Wang Jian, 2008. Composition and distribution of physiological race of Phytophthora infestans in the Haidong region of Qinghai province. Acta Phytopathologica Sinica. 38 (5), 553-556. http://zwblxb.periodicals.net.cn/default.html

Yu WenGui, Zou ChaYing, Zhao TongMin, Chen ZhiYi, Xue LinBao, Fan XueZhen, 2007. Identification of physiological races of Phytophthora infestans from tomato in Jiangsu Province and screening of resistance resource of tomato. Jiangsu Journal of Agricultural Sciences. 23 (6), 618-621. http://www.jaas.ac.cn

Zarzycka H, Sujkowski L S, 2000. A comparison of foliage resistance to Phytophthora infestans of some Dutch and Polish potato cultivars. Phytopathologia Polonica. 15-24.

Zeng HuiCai, Ho H H, Zheng FuyCong, 2009. A survey of Phytophthora species on Hainan Island of South China. Journal of Phytopathology. 157 (1), 33-39. http://www.blackwell-synergy.com/loi/jph DOI:10.1111/j.1439-0434.2008.01441.x

Zhang ZhiMing, Zhu JieHua, Song BoFu, Li YuQin, Tian ShiMin, Jiang HuShan, 2001. Further investigations on A2 mating type of Phytophthora infestans in China. Journal of Hebei Agricultural University. 24 (2), 32-37.

Zhang ZiJun, Zou QingDao, Guan TianShu (et al), 2007. Identification of physiological races and disease resistance of Phytophtora infestans on tomato in partial Liaoning Province. China Vegetables. 24-26.

Zhu GuiNing, Huang FuXin, Feng LanXiang, Qin BiXia, Yang YuHong, Chen YongHui, Lu XiuHong, 2008. Sensitivities of Phytophthora infestans to metalaxyl, cymoxanil, and dimethomorph. Agricultural Sciences in China. 7 (7), 831-840. http://www.sciencedirect.com/science/journal/16712927 DOI:10.1016/S1671-2927(08)60120-0

Zhu XiaoQiong, Che XingBi, Guo LiYun, Wang YingHua, 2004. Mating type of Phytophthora infestans from six provinces (cities) in China and their sensitivity to several fungicides. Plant Protection. 30 (4), 20-23.

Zhu XiaoQiong, Wang YingHua, Guo LiYun, 2006. Genetic diversity revealed by RAPD analysis among isolates of Phytophthora infestans from different locations in China. Acta Phytopathologica Sinica. 36 (3), 249-258.

Distribution Maps

Top of page
You can pan and zoom the map
Save map
Select a dataset
Map Legends
  • CABI Summary Records
Map Filters
Extent
Invasive
Origin
Third party data sources: