Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Phyllactinia guttata
(powdery mildew of hardwood trees)



Phyllactinia guttata (powdery mildew of hardwood trees)


  • Last modified
  • 20 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Natural Enemy
  • Preferred Scientific Name
  • Phyllactinia guttata
  • Preferred Common Name
  • powdery mildew of hardwood trees
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Fungi
  •     Phylum: Ascomycota
  •       Subphylum: Pezizomycotina
  •         Class: Leotiomycetes

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Powdery mildew symptoms caused by P. guttata; formation of cleistothecia on almond leaf.
TitleSymptoms on almond leaf
CaptionPowdery mildew symptoms caused by P. guttata; formation of cleistothecia on almond leaf.
CopyrightM. Fawaz Azmeh/University of Damascus
Powdery mildew symptoms caused by P. guttata; formation of cleistothecia on almond leaf.
Symptoms on almond leafPowdery mildew symptoms caused by P. guttata; formation of cleistothecia on almond leaf.M. Fawaz Azmeh/University of Damascus
CopyrightM. Fawaz Azmeh/University of Damascus
CleistotheciaM. Fawaz Azmeh/University of Damascus


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Preferred Scientific Name

  • Phyllactinia guttata (Wallr.) Lév.

Preferred Common Name

  • powdery mildew of hardwood trees

Other Scientific Names

  • Phyllactinia suffulta (Rebent.) Sacc.

International Common Names

  • Spanish: oidio (arboles planocaducifolios)
  • French: oïdium des arbres feuillus

Local Common Names

  • Germany: Mehltau: Laubhölzer

EPPO code

  • PHYLGU (Phyllactinia guttata)

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Fungi
  •         Phylum: Ascomycota
  •             Subphylum: Pezizomycotina
  •                 Class: Leotiomycetes
  •                     Order: Erysiphales
  •                         Family: Erysiphaceae
  •                             Genus: Phyllactinia
  •                                 Species: Phyllactinia guttata

Notes on Taxonomy and Nomenclature

Top of page Phyllactinia guttata is a compound species (a species complex). A comprehensive morphological and molecular revision of the whole complex is necessary. The teleomorph of P. guttata is rather uniform, providing little features for a further separation of this compound species into smaller units. Shin and Lee (2002) demonstrated that the shape and size of the penicillate cells of the ascomata are good diagnostic and possibly taxonomic features in Phyllactinia. However, the data available are not yet sufficient for final conclusions. The examinations carried out have been based on material from Korea. Examinations of additional collections are necessary to prove the variability, and material from other parts of the world, above all from Europe, must be included. Other useful diagnostic characters are connected with the anamorphs, which are mostly little known in Phyllactinia. For instance, Shin and Choi (2003) showed that Phyllactinia guttata s. lat. (P. suffulta f. pistaciae) on Pistacia vera represents a distinct new species, described as P. pistaciae H.D. Shin & Y.J. Choi, differing from P. guttata by the spirally twisted foot-cells of its conidiophores.


Top of page Mycelium on leaves, amphigenous, rarely caulicolous, mainly hypophyllous, narrow to moderately broad, effuse or forming patches, white to greyish white, evanescent to subpersistent; hyphae straight to flexuous, sinuous-geniculate, branched, septate, thin-walled, hyaline, cells ca. 40-80(-150) x 3-6(-10) µm; appressoria solitary or in opposite pairs, unlobed to hooked, occasionally forked or somewhat lobed, 5-12 µm diam.; conidiophores 50-350(-570) µm long and 5.5-9 µm wide, composed of (2-)3-5 cells of variable length, foot-cells (20-)50-200 µm long, basal septum often somewhat away from the branching point of the mycelium, following cells mostly shorter; conidia formed singly, clavate, fusiform-clavate or somewhat rhomboid in outline, apex rounded or with a small protrusion, 40-90(-125) x (10-)15-25(-30) µm; germ tubes mostly lateral, short, apex with a lobed appressorium. Ascomata (chasmothecia) mostly hypophyllous and scattered, 150-250(-280) µm diam., peridial cells rather obscure, irregularly polygonal, 8-20 µm diam., appendages more or less equatorial, 3-15(-18), acicular, with bulbous swelling, (20-)25-50(-60) µm diam., 1-2.5 times as long as the ascomatal diam., hyaline, terminal penicillate cells simple to moderately branched, mostly 40-60 µm long; asci 6-30, stalked, broadly clavate to subcylindrical, 60-100 x 25-40 µm, 2(-3)-spored; ascospores ellipsoid-ovoid, 25-45 x 14-25 µm.

Distribution Table

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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: 10 Jan 2020
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes


South AfricaPresentCABI Data Mining (Undated)


ArmeniaPresentAmano (1986)
AzerbaijanPresentAmano (1986)
ChinaPresentAmano (1986)
GeorgiaPresentAmano (1986)
IndiaPresentCABI Data Mining (Undated)
-Uttar PradeshPresentShweta Sharma et al. (2011)
IranPresentAmano (1986)
JapanPresentAmano (1986)
KazakhstanPresentAmano (1986)
KyrgyzstanPresentAmano (1986)
LebanonPresentAmano (1986)
South KoreaPresentAmano (1986)
TurkeyPresentErper et al. (2012); Amano (1986)
TurkmenistanPresentAmano (1986)


AlbaniaPresentAmano (1986)
AustriaPresentBraun (1995)
BelgiumPresentBraun (1995)
BulgariaPresentBraun (1995)
CzechiaPresentBraun (1995)
DenmarkPresentBraun (1995)
Federal Republic of YugoslaviaPresentBraun (1995)
FinlandPresentBraun (1995)
FrancePresentBraun (1995)
GermanyPresentBraun (1995)
GreecePresentBraun (1995)
HungaryPresentBraun (1995)
IrelandPresentBraun (1995)
ItalyPresentBraun (1995)
LatviaPresentBraun (1995)
LithuaniaPresentCABI Data Mining (Undated)
NetherlandsPresentBraun (1995)
NorwayPresentBraun (1995)
PolandPresentBraun (1995)
PortugalPresentAmano (1986)
RomaniaPresentBraun (1995)
RussiaPresentBraun (1995)
-SiberiaPresentAmano (1986)
SlovakiaPresentAmano (1986)
SpainPresentBraun (1995)
SwedenPresentBraun (1995)
SwitzerlandPresentCABI Data Mining (Undated)
UkrainePresentBraun (1995)
United KingdomPresentBraun (1995)

North America

CanadaPresentAmano (1986)
United StatesPresentCABI Data Mining (Undated)
-FloridaPresentCABI Data Mining (Undated)


New ZealandPresentBoesewinkel (1979)

South America

ChilePresent, LocalizedIPPC (2006)

Hosts/Species Affected

Top of page P. guttata occurs on a wide range of hosts covering numerous plant families, e.g., Betulaceae, Cornaceae, Fabaceae, Fagaceae, Meliaceae, Vitaceae, etc. (see Braun, 1987, 1995).

Host Plants and Other Plants Affected

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Growth Stages

Top of page Flowering stage, Fruiting stage, Vegetative growing stage


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Symptoms on flowering dogwood (Cornus florida) begin with raised circular areas, coated in a visible white powdery fungus. As they enlarge, the younger leaves appear distorted and necrotic brown lesions may form. Black specs may appear on the white fungus when mature cleistothecia develop. Flowers may also become infected, affecting their development and causing them to become distorted (McRitchie, 1994).

List of Symptoms/Signs

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SignLife StagesType
Inflorescence / distortion (non-graminaceous plants)
Leaves / fungal growth
Leaves / necrotic areas

Distribution Maps

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