Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Diaspidiotus perniciosus
(San José scale)



Diaspidiotus perniciosus (San José scale)


  • Last modified
  • 22 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Preferred Scientific Name
  • Diaspidiotus perniciosus
  • Preferred Common Name
  • San José scale
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Arthropoda
  •       Subphylum: Uniramia
  •         Class: Insecta
  • There are no pictures available for this datasheet

    If you can supply pictures for this datasheet please contact:

    CAB International
    OX10 8DE
  • Distribution map More information

Don't need the entire report?

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

Generate report


Top of page

Preferred Scientific Name

  • Diaspidiotus perniciosus (Comstock) Cockerell, 1899; Danzig, 1993

Preferred Common Name

  • San José scale

Other Scientific Names

  • Aonidia fusca Maskell, 1895
  • Aonidiella fusca (Maskell) Berlese & Leonardi, 1898
  • Aonidiella perniciosa (Comstock) Balachowsky & Mesnil, 1935
  • Aspidiotus (Comstockaspis) perniciosus (Comstock) Borschenius, 1935
  • Aspidiotus (Diaspidiotus) andromelas Cockerell, 1897
  • Aspidiotus (Diaspidiotus) perniciosus (Comstock) Brain, 1918
  • Aspidiotus (Hemiberlesiana) perniciosus (Comstock) Thiem & Gerneck, 1934
  • Aspidiotus (Quadraspidiotus) perniciosus (Comstock) Merril, 1953
  • Aspidiotus albopunctatus Cockerell, 1896
  • Aspidiotus fuscus (Maskell) Ferris, 1941
  • Aspidiotus perniciosus Comstock, 1881
  • Comstockaspis perniciosa (Comstock) MacGillivray, 1921
  • Hemiberlesia perniciosa (Comstock) Lindinger, 1957
  • Quadraspidiotus (Aspidiotus) perniciosus (Comstock) Rahman & Ansari, 1941
  • Quadraspidiotus perniciosus (Comstock) Ferris, 1938

International Common Names

  • English: California scale (Russia); Chinese scale; perniciosus scale
  • Russian: Kaliforniyskaya schitova
  • Portuguese: piolho de San José

Local Common Names

  • Denmark: san José skjoldlus
  • Finland: hirmukilpikirva
  • France: cochenille de San José; pou de San José
  • Germany: Kalifornische Schildlaus; San José Schildlaus
  • Hungary: Kaliforniai pajzstetü
  • Italy: cocciniglia di San José; pidochio di San José
  • Japan: Sanhoze kaigaramusi
  • Netherlands: San José schildluis
  • Norway: san-José skjoldlus
  • Spain: cochinilla de San José; escama de San José; piojo de San José
  • Sweden: san José-sköldlus
  • Turkey: san Jose kabuklu biti

EPPO code

  • QUADPE (Quadraspidiotus perniciosus)

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Arthropoda
  •             Subphylum: Uniramia
  •                 Class: Insecta
  •                     Order: Hemiptera
  •                         Suborder: Sternorrhyncha
  •                             Unknown: Coccoidea
  •                                 Family: Diaspididae
  •                                     Genus: Diaspidiotus
  •                                         Species: Diaspidiotus perniciosus

Notes on Taxonomy and Nomenclature

Top of page
Taxonomists disagree as to the generic placement of D. perniciosus. Danzig (1993) put it in Diaspidiotus, whereas Kosztarab (1996) left it in the widely used Quadraspidiotus genus. For further information see Bazarov and Shmelev (1971), Borchsenius (1966) and Kosztarab and Kozar (1988).


Top of page
The testa of the female is almost circular, slightly convex, light to dark grey, diameter ca 1.5-2.2 mm. Exuviae central or subcentral, the first-instar exuviae has a craterlike appearance. Young adult female pear-shaped, yellow; egg-laying females almost circular. Pygidium with two pairs of well-developed lobes, notched on outer margin. Plates between lobes partly pointed or fimbriated. Perivulvar pores absent (Kosztarab and Kozar, 1988).

The adult male was described by Bustshik (1958) and Gauri (1962). Morphometric analyses and a key for Quadraspidiotus (=Diaspidiotus) males are given by Kozar et al. (1996). The male is similar to the male of D. ostreaeformis, but the third segment of the antennae is shorter and elliptical in shape. For a long time there was no possibility of identifying the male and female in the first-instar stages. Later, Stoetzel and Davidson (1974) found some microscopic characters for separating the different sexes, and supposed these to be general for all members of the Aspidiotini. However, Kozar et al. (1996) found that first-instar female larva of D. perniciosus differs from other species in at least one character (an extra pair of dorsal setae on the second segment).


Top of page
D. perniciosus originated from Eastern Asia and was accidentally introduced to the USA, and subsequently to other parts of the world including Argentina, Australia and New Zealand. It is widely distributed in the Palearctic and Nearctic regions (Kozar, 1990a). There are many publications about its detailed distribution and importance in different parts of the world (Konstantinova, 1976; Baker, 1977; Chowdhuri, 1977; Kozar and Konstantinova, 1981; Anon., 1986; APPPC, 1987; Kozar and Drozdjak, 1988; Davidson and Miller, 1990; Kozar et al., 1994; Mani et al., 1995).

The distribution map includes records based on specimens of D. perniciosus from the collection in the Natural History Museum (London, UK): dates of collection are noted in the List of Countries (NHM, various dates).

See also CABI/EPPO (1998, No. 131).

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: 19 Jul 2021
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes


AlgeriaPresent, Widespread
Congo, Democratic Republic of thePresent
Congo, Republic of thePresent
MoroccoPresent, Localized
South AfricaPresent
TunisiaPresent, Widespread
ZimbabwePresent, Localized


ChinaPresent, Widespread
-Inner MongoliaPresent
Hong KongPresent, Few occurrences
IndiaPresent, Widespread
-Andhra PradeshPresent
-Himachal PradeshPresent
-Jammu and KashmirPresent
-Tamil NaduPresent
-Uttar PradeshPresent
-West BengalPresent
IranPresent, Localized
JapanPresent, Widespread
-HokkaidoPresent, Widespread
-HonshuPresent, Widespread
-KyushuPresent, Widespread
-ShikokuPresent, Widespread
JordanAbsent, Unconfirmed presence record(s)
KazakhstanPresent, Localized
North KoreaPresent
South KoreaPresent
TaiwanAbsent, Formerly present
TajikistanPresent, Localized
TurkeyPresent, Localized
UzbekistanPresent, Localized
YemenAbsent, Eradicated


AustriaPresent, Widespread
BelgiumAbsent, Formerly present
BulgariaPresent, LocalizedFirst reported: 196*
CroatiaPresent, Widespread
CyprusAbsent, Confirmed absent by survey
CzechiaPresent, Localized
DenmarkAbsent, Formerly present
FrancePresent, Widespread
GermanyPresent, Widespread1946
GreecePresent, Localized
HungaryPresent, Widespread1928
ItalyPresent, Widespread
LithuaniaAbsent, Intercepted only
MoldovaPresent, Localized
NetherlandsPresent, Localized
NorwayAbsent, Intercepted only
PolandAbsent, Eradicated
PortugalPresent, Widespread
RomaniaPresent, Widespread
RussiaPresent, Localized
-Central RussiaPresent
-Eastern SiberiaAbsent, Formerly present
-Russian Far EastPresent
-Southern RussiaPresent
SerbiaPresent, Widespread
Serbia and MontenegroPresent, Widespread
SloveniaPresent, Localized
SpainPresent, Localized
-Canary IslandsPresent, Localized
SwedenAbsent, Intercepted only
UkrainePresent, Localized1952
United KingdomAbsent, Intercepted only

North America

CanadaPresent, Localized
-British ColumbiaPresent, Localized
-Nova ScotiaAbsent, Eradicated
-OntarioPresent, Localized
-QuebecPresent, Localized
United StatesPresent, Widespread
-New JerseyPresent
-New YorkPresent
-West VirginiaPresent


AustraliaPresent, Localized
-New South WalesPresent
-QueenslandPresent, Widespread
-South AustraliaPresent
-TasmaniaAbsent, Eradicated
-VictoriaPresent, Localized
-Western AustraliaPresent
New CaledoniaPresent
New ZealandPresent, Widespread1908

South America

ArgentinaPresent, Widespread
BoliviaPresent, Widespread
BrazilPresent, Widespread
-Minas GeraisPresent
-Rio de JaneiroPresent
-Rio Grande do SulPresent
-Santa CatarinaPresent
-Sao PauloPresent
ChilePresent, Widespread
EcuadorPresent, Localized
ParaguayPresent, Localized
PeruPresent, Widespread
UruguayPresent, Widespread
VenezuelaPresent, Widespread

Risk of Introduction

Top of page
This species is considered an object of quarantine regulations on almost all continents. In the past few years, however, the European Union has deleted it from its quarantine list, because of its presence in most of the member countries.

Hosts/Species Affected

Top of page
D. perniciosus is a polyphagous species. The host plant range could probably be much wider. However, on some of the recorded host plants this insect cannot finish development, which means that these species are not true host plants. The importance of the host plant is different in different parts of the world, so for each region only the local literature sources can give a true picture. In general, this species is very dangerous on deciduous fruit trees including apple, pear, peach, plum, currants and some woody ornamental plants (Konstantinova, 1976; APPPC, 1987; Davidson and Miller, 1990; Kozar, 1990a; Kosztarab, 1996). Different varieties of fruit species show different susceptibility in different parts of the world, and many fruit species have been studied in this respect (Bichina and Gatina, 1976; Shalamberidze, 1978; Verma and Sriravasta, 1990).

Host Plants and Other Plants Affected

Top of page
Plant nameFamilyContextReferences
Acacia (wattles)FabaceaeOther
Acer (maples)AceraceaeOther
Aesculus (buckeye)HippocastanaceaeOther
Alnus (alders)BetulaceaeOther
Aloe (grey alder)AloaceaeOther
Althaea (hollyhocks)MalvaceaeOther
Amelanchier (serviceberries)RosaceaeOther
Antirrhinum (snapdragon)ScrophulariaceaeOther
Aristolochia (dutchman's pipe)AristolochiaceaeOther
Asclepias (Silkweed)AsclepiadaceaeOther
Asparagus officinalis (asparagus)LiliaceaeOther
Bambusa (bamboo)PoaceaeOther
Berberis (barberries)BerberidaceaeOther
Betula (birches)BetulaceaeOther
Buddleia (Butterflybush)LoganiaceaeOther
Buxus (box)BuxaceaeOther
Callistemon (Bottle brush)MyrtaceaeOther
Carpinus (hornbeams)BetulaceaeOther
Carya (hickories)JuglandaceaeOther
Caryopteris (blue-beard)LamiaceaeOther
Castanea (chestnuts)FagaceaeOther
Ceanothus (white-thorn)RhamnaceaeOther
Cedrus (cedars)PinaceaeOther
Celtis (nettle tree)UlmaceaeOther
Cephalanthus (buttonbush)RubiaceaeOther
Cercis (redbud)FabaceaeOther
Chaenomeles (flowering quinces)RosaceaeOther
Chamaecyparis (false cypress)CupressaceaeOther
Chrysanthemum (daisy)AsteraceaeOther
Cistus (rockrose)CistaceaeOther
Clerodendrum (Fragrant clerodendron)LamiaceaeOther
Convolvulus (morning glory)ConvolvulaceaeOther
Cornus (Dogwood)CornaceaeOther
Crataegus (hawthorns)RosaceaeOther
Cupressus (cypresses)CupressaceaeOther
Cydonia (quince)RosaceaeOther
Cytisus (Broom)FabaceaeOther
Daucus (carrot)ApiaceaeOther
Diervilla (bush-honeysuckle)CaprifoliaceaeOther
Diospyros (malabar ebony)EbenaceaeOther
Erica (heaths)EricaceaeOther
Erigeron (Fleabane)AsteraceaeOther
Euonymus (spindle trees)CelastraceaeOther
Euphorbia (spurges)EuphorbiaceaeOther
Fagus (beeches)FagaceaeOther
Forsythia (golden bells)OleaceaeOther
Fragaria (strawberry)RosaceaeOther
Fraxinus (ashes)OleaceaeOther
Gaylussacia (huckleberry)EricaceaeOther
Genista (broom)FabaceaeOther
Hamamelis (witchhazel)HamamelidaceaeOther
Hedera (Ivy)AraliaceaeOther
Hibiscus (rosemallows)MalvaceaeOther
Hydrangea (hydrangeas)HydrangeaceaeOther
Hypericum (st Johnsworts)ClusiaceaeOther
Ilex (Holly)AquifoliaceaeOther
Inula (Elecampane)AsteraceaeOther
Jasminum (jasmine)OleaceaeOther
Juglans (walnuts)JuglandaceaeOther
Juniperus (junipers)CupressaceaeOther
Kalmia (laurel)EricaceaeOther
Laburnum anagyroides (laburnum)FabaceaeOther
Larix (larches)PinaceaeOther
Laurus (laurel)LauraceaeOther
Ligustrum (privet)OleaceaeOther
Lilium (lily)LiliaceaeOther
Lindera (spicebush)LauraceaeOther
Liquidambar (amber tree)HamamelidaceaeOther
Liriodendron (tulip tree)MagnoliaceaeOther
Lonicera (honeysuckles)CaprifoliaceaeOther
Lycium (boxthorn)SolanaceaeOther
Maclura (osage-orange)MoraceaeOther
Mahonia (holly grape)BerberidaceaeOther
Malus (ornamental species apple)RosaceaeMain
Malus domestica (apple)RosaceaeUnknown
Malva (mallow)MalvaceaeOther
Mespilus (medlar)RosaceaeOther
Morus (mulberrytree)MoraceaeMain
Myrica (waxmyrtles)MyricaceaeOther
Myrtus (myrtle)MyrtaceaeOther
Nerium (oleander)ApocynaceaeOther
Nyssa (tupelo)CornaceaeOther
Olea (olive)OleaceaeOther
Paeonia (peonies)PaeoniaceaeOther
Panicum (millets)PoaceaeOther
Petroselinum (parsley)ApiaceaeOther
Phellodendron (cork tree)RutaceaeOther
Philadelphus coronarius (mock orange)HydrangeaceaeOther
Picea (spruces)PinaceaeOther
Pinus (pines)PinaceaeOther
Piper (pepper)PiperaceaeOther
Platanus (planes)PlatanaceaeOther
Polygonum (knotweed)PolygonaceaeOther
Populus (poplars)SalicaceaeOther
Potentilla (Cinquefoil)RosaceaeOther
Prunus (stone fruit)RosaceaeMain
Prunus avium (sweet cherry)RosaceaeOther
Prunus domestica (plum)RosaceaeOther
Prunus laurocerasus (cherry laurel)Other
Prunus persica (peach)RosaceaeOther
Prunus salicina (Japanese plum)RosaceaeOther
Pyracantha (Firethorn)RosaceaeOther
Pyrus (pears)RosaceaeMain
Pyrus communis (European pear)RosaceaeOther
Rhododendron (Azalea)EricaceaeOther
Rhus (Sumach)AnacardiaceaeOther
Ribes (currants)GrossulariaceaeMain
Robinia (locust)FabaceaeOther
Rosa (roses)RosaceaeOther
Rubus (blackberry, raspberry)RosaceaeMain
Rudbeckia (coneflower)AsteraceaeOther
Salix (willows)SalicaceaeOther
Sambucus (Elderberry)CaprifoliaceaeOther
Schinus (pepper tree)AnacardiaceaeOther
Smilax (greenbriar)SmilacaceaeOther
Solanum (nightshade)SolanaceaeOther
Sorbus (rowan)RosaceaeOther
Symphoricarpos (snowberry)CaprifoliaceaeOther
Tamarix (tamarisk)TamaricaceaeOther
Taxodium (pondcypress)TaxodiaceaeOther
Taxus (yew)TaxaceaeOther
Tilia (limes)TiliaceaeOther
Tsuga (hemlocks)PinaceaeOther
Ulmus (elms)UlmaceaeOther
Urtica spp.UrticaceaeOther
Vaccinium (blueberries)EricaceaeMain
Vinca (periwinkle)ApocynaceaeOther
Vitis (grape)VitaceaeOther

Growth Stages

Top of page
Fruiting stage, Post-harvest, Vegetative growing stage


Top of page
D. perniciosus infests mostly the bark on the stem and branches of the tree. Sometimes it can be found on the fruits, where it causes red spot. In cases of heavy infestation, the branches can die.

The red spots on the fruits and leaves do not cause great damage; however, it can cause problems in quarantine inspection, because the species is a quarantine insect in many countries.

List of Symptoms/Signs

Top of page
SignLife StagesType
Fruit / lesions: black or brown
Leaves / abnormal colours
Leaves / abnormal leaf fall
Leaves / necrotic areas
Stems / dieback
Stems / discoloration of bark
Whole plant / dwarfing
Whole plant / early senescence
Whole plant / plant dead; dieback

Biology and Ecology

Top of page
D. perniciosus has 1-5 generations in different parts of the world. Its development differs in these regions and detailed information can be found only in local publications. It overwinters in colder countries as first-instar larvae. The female has three stages (first- and second-instar larvae and the adult) while the male has five (first- and second-instar larvae, the pronymph, nymph and adult). In central Europe, the adults appear at the end of April, and in northern Europe 1 or 2 months later. The crawlers continue to appear for 1-2 months: the females have about 100 crawlers. The development of one generation requires about 45-80 days (Kosztarab and Kozar, 1988).

The first-instar larva is the dispersal phase. It can be distributed by wind, birds or flying insects. The most important means of transport, however, is infested nursery material. Using this method, this pest was accidentally introduced throughout the world.

The development was studied in detail in different countries. A comprehensive biological monograph has not yet been published. There are some smaller, but important, works available in different countries: For example, see Benassy (1969). In general, development starts at 7°C and this pest is tolerant of cold winter temperatures.

Natural enemies

Top of page
Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Ablerus clisiocampae Parasite Adults; Arthropods|Nymphs
Ablerus kashmirensis Parasite Adults; Arthropods|Nymphs India; Jammu and Kashmir apples
Anagrus armatus Parasite Eggs
Anagrus atomus Parasite Eggs
Anagrus epos Parasite Eggs
Anthemus affinis Parasite
Aphytis aonidiae Parasite Adults; Arthropods|Nymphs
Aphytis chilensis Parasite
Aphytis diaspidis Parasite
Aphytis hispanicus Parasite
Aphytis maculicornis Parasite
Aphytis melanostictus Parasite Adults; Arthropods|Nymphs
Aphytis mytilaspidis Parasite Adults; Arthropods|Nymphs India fruit trees
Aphytis paramaculicornis Parasite
Aphytis proclia Parasite Adults; Arthropods|Nymphs India; Jammu and Kashmir; Republic of Georgia apples; fruit trees
Aphytis sp. nr. diaspidis Parasite Adults; Arthropods|Nymphs India fruit trees
Aphytis vandenboschi Parasite Adults; Arthropods|Nymphs
Azotus dozieri Parasite Adults; Arthropods|Nymphs
Azotus perspeciosus Parasite Adults; Arthropods|Nymphs
Chilocorus bijugus Predator Adults; Arthropods|Nymphs Himachal Pradesh; India; USSR
Chilocorus circumdatus Predator Adults; Arthropods|Nymphs Australia apricots; peaches; plums
Chilocorus geminus Predator Adults; Arthropods|Nymphs China; Xinjiang; USSR Ziziphus
Chilocorus infernalis Predator Adults; Arthropods|Nymphs Pakistan; USSR
Chilocorus kuwanae Predator Adults; Arthropods|Nymphs India; USA fruit trees
Chilocorus nigrita Predator Adults; Arthropods|Nymphs
Chilocorus renipustulatus Predator Adults; Arthropods|Nymphs Europe fruit trees
Chilocorus similis Predator Adults; Arthropods|Nymphs Czechoslovakia; USA fruit trees
Chilocorus stigma Predator Adults; Arthropods|Nymphs Australia apricots; peaches; plums
Chrysopa orestes Predator Adults; Arthropods|Nymphs
Coccidencyrtus steinbergi Parasite
Coccidophilus citricola Predator Adults; Arthropods|Nymphs
Coccinella septempunctata Predator Adults; Arthropods|Nymphs
Coccophagoides murtfeldtae Parasite Adults; Arthropods|Nymphs
Comperiella bifasciata Parasite New Zealand pears
Crematogaster subdentata Predator Adults; Arthropods|Nymphs
Cybocephalus fodori Predator Adults; Arthropods|Nymphs
Cybocephalus gibbulus Predator Adults; Arthropods|Nymphs India fruit trees
Encarsia aurantii Parasite
Encarsia citrina Parasite Adults; Arthropods|Nymphs New Zealand pears
Encarsia diaspidicola Parasite
Encarsia fasciata Parasite Adults; Arthropods|Nymphs France; Germany fruit trees
Encarsia gigas Parasite
Encarsia perniciosi Parasite Adults; Arthropods|Nymphs Austria; Bulgaria; Chile; Czechoslovakia; France; Germany; Greece; India; India; Jammu and Kashmir; Italy; New South Wales; New Zealand; Pakistan; Republic of Georgia; South Africa; Spain; Switzerland; USSR; Yugoslavia apples; fruit trees; pears
Euussuria shutovae Parasite
Exochomus uropygialis Predator Adults; Arthropods|Nymphs
Habrolepis aspidioti Parasite California fruit trees
Hemisarcoptes malus Parasite
Marietta carnesi Parasite Adults; Arthropods|Nymphs India; Jammu and Kashmir apples
Marietta mexicana Parasite Adults; Arthropods|Nymphs
Orius insidiosus Predator Adults; Arthropods|Nymphs USA; Virginia apples
Pentilia insidiosa Predator Adults; Arthropods|Nymphs Pakistan apples
Pharoscymnus flexibilis Predator Adults; Arthropods|Nymphs India
Pteroptrix chinensis Parasite Adults; Arthropods|Nymphs
Rhyzobius lindi Predator Adults; Arthropods|Nymphs California fruit trees
Rhyzobius lophanthae Predator Adults; Arthropods|Nymphs Czechoslovakia; Europe; India fruit trees
Scymnus gracilis Predator Adults; Arthropods|Nymphs
Sticholotis madagassa Predator Adults; Arthropods|Nymphs India
Sticholotis marginalis Predator Adults; Arthropods|Nymphs
Teleterebratus perversus Parasite
Thomsonisca pallipes Parasite USSR
Thomsonisca shutovae Parasite USSR fruit trees
Thomsonisca typica Parasite

Notes on Natural Enemies

Top of page
D. perniciosus has a high number of parasitoids and predators, which have been studied in detail, especially in the Palearctic region (Trjapitzin, 1978; Kosztarab and Kozar, 1988). There are many papers on natural enemies of this pest in different countries (Ahmad and Ghani, 1971; Rosen and De Bach, 1976; Folkina, 1978; Myartzeva, 1978; Trjapitzin, 1978; Popova, 1979; Darling and Johnson, 1984; Katsoyanos, 1984; Yasnosh, 1985; Bhagat et al., 1988; Titayavan and Davis, 1988; Thakur et al., 1989; Sharma et al., 1990; Bull et al., 1993).

These natural enemies are efficient regulators of D. perniciosus, and they keep down the population density in natural habitats. Where chemical control is inefficient against D. perniciosus, but kills the natural enemies, local outbreaks can occur in orchards. The efficiency of natural enemies is also reduced in urban regions by pollution, where subsequently the pest can cause damage on ornamental plants.

There have been many successful special biological control projects against D. perniciosus in different parts of the world, especially in the USA, Europe and Russia. Usually the main specialized parasitoid Encarsia perniciosi was reared, released and established, according to Rosen (1991). Concerning the list of parasitoids it is important to notice that some parasitoids are only parasitoids, but that others may be both parasitoids and hyperparasitoids, and in many published cases this is not clarified.

All data cited in the table are based on original publications. Therefore there could be misidentifications of the parasitoids or even the host. The generic names also could be not updated. Very often the origin, and the real distribution of the natural enemies cannot be established from the original source and needs to be surveyed. The time of the introduction into a particular country also needs clarification: for example there was not a special release of Encarsia perniciosi in Hungary, but the parasitoid appeared very quickly because of the mass release in the neighbouring countries.


Top of page
Crop loss caused by D. perniciosus on different trees is difficult to assess. The trees lose their vigour and have a shorter lifespan. Shortly after introduction to a new country, this pest can infest and kill whole trees and plantations. This species is a quarantine pest in different parts of the world. The import and export of infested fruits or plants could be refused.

Local outbreaks have been observed in different parts of the world on fruit trees and ornamental plants, as in Hungary (Kozar and Drozdjak, 1988), Switzerland (Kozar et al, 1994; Mani et al, 1995), the European part of Russia (Kozar and Konstantinova, 1981), Australia (Baker, 1977) and Canada (Ker and Sears, 1986).

Detection and Inspection

Top of page
In cases of heavy infestation, greyish scales can be found on the bark of the trees. Lighter infestations can be found by laboratory examination with stereomicroscope analyses of the branches, following the survey system described in detail by Kozar (1990b, c). The pheromone of the species is also known. The different compounds of the D. perniciosus pheromone attract the males and parasitoids. Colour and sticky traps have been developed to follow the flight of the males and parasitoids (Kozar, 1990c). The red spots on the fruits can also indicate infestation.

Similarities to Other Species/Conditions

Top of page
D. perniciosus can be identified only by its characteristics on microscope slides. A method of slide mounting is described by Kosztarab and Kozar (1988). This species is often found together with other species of Diaspidiotus. According to microscopic characters, it is easy to distinguish, because D. perniciosus has no groups of perivulvar pores, which are present in other Diaspidiotus species infesting fruit trees. D. perniciosus overwinters as first-instar larvae, whereas other species overwinter as second instars or females. D. perniciosus is ovoviviparous, whereas the other species lay eggs.

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.

Regulatory Control (Plant Quarantine and Certification)

Many different countries have special regulations against this pest, the most detailed elaborated by EPPO (1996).

Cultural Control and Sanitary Methods

Scale-free nursery material is very important, because young plants can die very quickly once infested. Cutting the heavily infested parts of the trees and cleaning the bark from infestation can help to increase the efficiency of chemical treatments. There is discussion in the literature about the role of the surrounding infested vegetation: it is partly a source for the re-infestation of the plantations, but it could also be a refuge for the natural enemies.

Host-Plant Resistance

There are no resistant varieties against this pest. There are several tolerant varieties of different fruit species; however, these varieties are not usually very marketable.

Biological Control

Biological control against D. perniciosus is well studied and is one of the more successful projects of this nature in the world, especially using Encarsia perniciosi. Such programmes can give substantially good results only after a relatively long time, and only in the absence of toxic insecticides. The additional release of different predators, and conserving the local natural enemies can increase the efficiency of control.

Chemical Control

For a long time fumigation of seedlings was the most important means of preventing early infestation. For this purpose different chemicals were used, such as hydrogen cyanide, fostoxin or methylbromide (Obretenchev and Stanev, 1992; Anon., 1993; Mordkovich and Chernei, 1993). There are also quarantine recommendations, or requirements for treatment of the fruits to prevent infestation by this pest (although the infestation of plants from fruits has never been proved). For this purpose different methods were proposed as irradiation, fumigation, cold treatment or warm treatment (Angerilli and Fitzgibbon, 1990 and others).

For the treatment of plantations, dormant oil spraying was proposed and is very effective (Ker and Sears, 1986; Chander and Kakar, 1994; Hippe et al., 1995; Isufi and Myrtal, 1996). Almost all the toxic insecticides used (phosphororganics, carbamates, pyrethroids) are effective against crawlers of this pest. The use of these chemicals in summer against other pests such as codling moth, leafrollers, leafminers or mites can often keep down the density of this pest.

Early Warning Systems, Field Monitoring/Economic Threshold Levels

Monitoring and forecasting systems were analysed in detail by Kozar (1990b, c). It was established that there are several methods for monitoring and detection, like white sticky traps (for the males), suction traps (for the males and parasitoids). Pheromone traps collecting the males and parasitoids are the most widely used. Because of the quarantine requirements an economic threshold was not developed. However, in some countries (where there is no strict prohibition, like in Hungary or Russia) there is a special quarantine threshold, only 5% of the fruits can be infested with this scale.

IPM Programmes

Special integrated control projects have been developed against orchard pests including scale insects (Kozar and Varjas, 1976; Ripa and Caltagirone, 1994; Paloukis and Navzoridis, 1995; Jenser et al., 1997). These programmes propose the use of new, selective, non-toxic products (different types of juvenoids and chitin inhibitors, for example) against pests, which have a good effect against different groups of pests, including scale insects. In these orchards the introduced and local natural enemies could reach a high density and reduce the density of pests. If such programmes are implemented, it is possible to have fruits with very low numbers of D. perniciosus.


Top of page

1993. Quarantine procedure. Hydrogen cyanide fumigation of woody plants to control Quadraspidiotus perniciosus. Bulletin OEPP, 23(2):204

Ahmad R, Ghani MA, 1971. The biology of Sticholotis marginalis Kapur (Col.:Coccinellidae). Technical Bulletin of the Commonwealth Institute of Biological Control, No. 14:91-95

Angerilli NPD, Fitzgibbon F, 1990. Effects of cobalt gamma radiation on San Jose scale (Homoptera: Diaspididae) survival on apples in cold and controlled-atmosphere storage. Journal of Economic Entomology, 83(3):892-895.

Anon., 1986. Quadraspidiotus perniciosus. Distribution Maps of Pests. UK, CAB International Institute of Entomology, No. 7. Wallingford, UK: CAB International.

APPPC, 1987. Insect pests of economic significance affecting major crops of the countries in Asia and the Pacific region. Technical Document No. 135. Bangkok, Thailand: Regional Office for Asia and the Pacific region (RAPA).

Baker G, 1977. Distribution of San Jose scale, Quadraspidiotus perniciosus (Comst.), in the Adelaide Hills. Agricultural Record, 4(7):54-56

Bazarov BB, Shmelev GP, 1971, Akad. Nauk Tadzh. SSR Inst. Zool. Parazitol. 11:220.

Benassy C, 1969. Contribution a l'etude du peuplement d'un vegetal par Quadraspidiotus perniciosus Comst. (Homoptera Coccidae) et a l'influence de ce dennier sur son hote. These, Faculte des Sciences de L'Universite de Lyon, No 319.

Bhagat KC, Masoodi MA, Koul VV, 1988. A note on the occurrence of a coccinellid predator in Kashmir. Current Research, University of Agricultural Sciences, Bangalore, 17(5):49-51

Bichina TI, Gatina Esh, 1976. Varietal susceptibility of apple trees to San Jose scale and its integrated control. Ustoichivost' Vinograda i Plodov. Kul'tur k Zabolevaniyam i Vreditelyam. 124-137. Stiinca, Kishinev: Moldavian SSR.

Borchsenius NS, 1966. A Catalogue of the Armoured Scale Insects (Diaspidoidea) of the World. (In Russian). Leningrad, Russia: Akademii Nauk SSR Zoologicheskogo Instituta, 449 pp.

Bull BC, Raupp MJ, Hardin MR, Sadof CS, 1993. Suitability of five horticulturally important armored scale insects as hosts for an exotic predaceous lady beetle. Journal of Environmental Horticulture, 11(1):28-30

Bustshik TN, 1958. A contribution to the comparative morphology of the males of the scale insects (Homoptera, Coccoidea, Diaspididae). Trudy Akad. Nauk. SSSR. Vsesoiuzn. Entomol. Obsh., 46:162-269.

CABI/EPPO, 1998. Distribution maps of quarantine pests for Europe (edited by Smith IM, Charles LMF). Wallingford, UK: CAB International, xviii + 768 pp.

Chander R, Kakar KL, 1994. Requirement of dormant spray oil for the suppression of San Jose scale, Quadraspidiotus perniciosus (Comstock) on apple. Journal of Insect Science, 7(2):222-223; 2 ref.

Chowdhuri AN, 1977. San Jose scale. Quadraspidiotus perniciosus (Comstock). Science and Culture, 43:512.

Danzig EM, 1993. Fauna of Russia. Families Phoenicoccidae and Diaspididae. St. Petersburg, Russia: Nauka, 450 pp.

Darling DC, Johnson NF, 1984. Synopsis of Nearctic Azotinp (Hymenoptera: Aphelinidae). Proceedings of the Entomological Society of Washington, 86(3):555-562.

Davidson JA, Miller DR, 1990. Ornamental plants. In: Rosen D, ed. Armoured Scale Insects, their Biology, Natural Enemies and Control. Vol. 4B. Amsterdam, Netherlands: Elsevier, 603-632.

EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization.

Fol'kina MYa, 1978. A case of mass extermination of the San Jose scale (Quadraspidiotus perniciosus) by the ant Crematogaster subdentata. Zoologicheskii Zhurnal, 57(2):301

Ghauri M, 1962. The Morphology and Taxonomy of Male Scale Insects (Homoptera, Coccoidea). British Museum (Natural History). Dorking, UK: Adlard and Son, 221 pp.

Hippe C, Schwaller F, Mani E, Kull H, Kozar F, 1995. Control of native oyster scale insects. Obst- und Weinbau, 131(4):84-85

Isufi E, Myrta A, 1996. The defence of fruit trees in Albania: problems and prospects. Informatore Fitopatologico, 46(1):33-36; 5 ref.

Jenser G, Balßzs K, ErdTlyi C, Haltrich A, Kozßr F, Mark= V, Rßcz V, Samu F, 1997. The effect of an integrated pest management program on the arthropod populations in a Hungarian apple orchard. Zahradnictvi^acute~, 24(2):63-76; 16 ref.

Katsoyannos P, 1984. Notes on life history and field efficiency of Cybocephalus fodori predator of Quadraspidiotus perniciosus in northern Greece. Entomologia Hellenica, 2(2):35-40

Ker KW, Sears MK, 1986. Effectiveness of superior oil applied to apple for control of the San Jose scale, Quadraspidiotus perniciosus, and the European fruit scale, Quadraspidiotus ostrepformis (Homoptera: Diaspididae). Proceedings of the Entomological Society of Ontario, 117:45-48

Knight AL, Christianson BA, Unruh TR, Puterka G, Glenn DM, 2001. Impacts of seasonal kaolin particle films on apple pest management. Canadian Entomologist, 133(3):413-428.

Konstantinova GM, 1976. Coccids - pests of apple. Zashchita Rastenii, 12:49-50.

Kosztarab M, 1996. Scale Insects of North Eastern North America: identification, biology, and distribution. Martinsville, USA: Virginia Museum of Natural History, 650 pp.

Kosztarab M, Kozar F, 1988. Scale insects of Central Europe. Dordrecht, Netherlands: Kluwer Academic Publishers, 455 pp.

Kozar F, Brown MW, Lightner G, 1994. Spatial distribution of homopteran pests and beneficial insects in an orchard and its connection with ecological plant protection. Journal of Applied Entomology, 117(5):519-529

Kozár F, Drozdjak J, 1988. Peculiarities in the distribution of scale-insects (Homoptera: Coccoidea) on deciduous fruit trees in Hungary. Acta Phytopathologica et Entomologica Hungarica, 23(1-2):187-210

Kozár F, Guignard E, Bachmann F, Mani E, Hippe C, 1994. The scale insect and whitefly species of Switzerland (Homoptera: Coccoidea and Aleyrodoidea). Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 67(1-2):151-161; 24 ref.

Kozár F, Konstantinova GM, 1981. The scale insects (Homoptera: Coccoidea) of deciduous fruit orchards in some European countries. (Survey of scale insect (Homoptera: Coccoidea) infestations in European orchards No. III.). Acta Phytopathologica Academiae Scientiarum Hungaricae, 16(1/2):211-222.

Kozar F, Varjas L, 1976. Laboratory experiments with juvenoids on the San Jose scale, Quadraspidiotus perniciosus Comst. Acta Phytopathologica Academiae Scientiarum Hungaricp, 11(3-4):295-303.

Kozßr F, 1990. Deciduous fruit trees. In: Rosen D, ed. Armored Scale Insects their Biology, Natural Enemies and Control. Vol. 4B. Amsterdam, Netherlands: Elsevier Science Publishers B.V., 593-602.

Kozßr F, 1990. Forecasting and Monitoring Infestations. Forecasting. In: Rosen D, ed. Armored Scale Insects their Biology, Natural Enemies and Control. Vol. B. Amsterdam, Netherlands: Elsevier Science Publishers B.V., 335-340.

Kozßr F, 1990. Sampling and Census-Taking. In: Rosen D, ed. Armored Scale Insects their Biology, Natural Enemies and Control. Vol. B. Amsterdam, Netherlands: Elsevier Science Publishers B.V., 341-347.

Kozßr F, Hippe C, Mani E, 1996. Morphometric analyses of the males of Quadraspidiotus species (Hom., Diaspididae) found in European orchards or their vicinity. Journal of Applied Entomology, 120(7):433-437; 18 ref.

Mani E, Schwaller F, Baroffio C, Hippe C, 1995. The San Jose scale in German-speaking Switzerland: where do we stand today? Obst- und Weinbau, 131(10):264-267.

Mohammad Ullah M, 1988. Major insect pests and phytophagous mites associated with deciduous orchards in Afghanistan. Tropical Pest Management, 34(2):215-217, 243, 247

Mordkovich YaB, Chernei LB, 1993. Phostoxin for fumigation of planting stock. Zashchita Rastenii (Moskva), 12:30.

Myartseva SN, 1978. Two new species of the genus Coccidencyrtus (Hymenoptera, Encyrtidae) from Turkmenia. Zoologicheskii Zhurnal, 57(11):1735-1740

Nakahara S, 1982. Checklist of the Armored Scales (Homoptera: Diapididae) of the Conterminous United States. Washington, USA: USDA, Animal and Plant Health Inspection Service, Plant Protection and Quarantine, 110 pp.

New Zealand MAF Biosecurity, 2011. Pest watch: 2 November 2010 - 21 March 2011, 38(2):53-54.

Obretenchev D, Stanev M, 1992. Methyl-bromide gassing of planting fruit stock against the San Jose scale Quadraspidiotus perniciosus. Rasteniev"dni Nauki, 29(3/6):118-123.

Paloukis SS, Navrozidis EI, 1995. Effectiveness of a new insecticide (Diofenolan) for control of San JosT scale, Quadraspidiotus perniciosus (Comstock) (Diaspididae), on peach trees in northern Greece. Israel Journal of Entomology, 29:285-286; 2 ref.

Popova AI, 1979. Parasites of the males of the California scale Diaspidiotus perniciosus Comst. (Homoptera, Coccoidea). Entomologicheskoe Obozrenie, 58(3):538-547

Ripa S R, Caltagirone L, 1994. Implementation of integrated pest control. Revista Fruticola, 15(2):67-73

Rosen D, 1991. Armored Scale Insects, their Biology, Natural Enemies and Control. Vol. B. Amsterdam, The Netherlands: Elsevier Science Publishers B.V., 688 pp.

Rosen D, DeBach P, 1976. Biosystematic studies on the species of Aphytis (Hymenoptera: Aphelinidae). Mushi, 49(1):1-17.

Schönfeld U, 2015. Coccoidea species in Brandenburg. (Cocciden-arten in Brandenburg.) Journal für Kulturpflanzen, 67(10):337-341.

Shalamberidze NSh, 1978. The resistance of plum cultivars to San Jose scale. Sadovodstvo, Vinogradarstvo i Vinodelie Moldavii, 4:41.

Sharma DC, Rawat US, Pawar AD, 1990. Effect of temperature and humidity on the development, longevity and predatory potential of Pharoscymnus flexibilis Muls. on San Jose scale. Journal of Biological Control, 4(1):11-14

Sharma DR, 2011. New pest problems on fruit crops in Punjab. Journal of Insect Science (Ludhiana), 24(3):300-304.

Singh SS, Tiwari HC, Rai KM, 2001. Evaluation of some modern insecticides against San Jose scale, Quadraspidiotus perniciosus (Comstock) on apple. Journal of Entomological Research, 25(1):69-71.

Stoetzel MB, Davidson JA, 1974. Sexual dimorphism in all stages of the Aspidiotini (Homoptera: Diaspididae). Annals of the Entomological Society of America, 67(1):138-140

Thakur JN, Rawat US, Pawar AD, 1989. Investigations on the occurrence of natural enemies of San Jose scale, Quadraspidiotus perniciosus Comstock (Hemiptera: Coccidae) in Jammu & Kashmir and Himachal Pradesh. Entomon, 14(12):143-146

Titayavan M, Davis DW, 1988. Studies of a uniparental form of Aphytis vandenboschi (Hymenoptera: Aphelinidae), a parasite of the San Jose scale in northern Utah. Great Basin Naturalist, 48(3):388-393

Trjapitzin VA, 1978. Superfamily Chalcidoidea. In: Medvedev GS, ed. Insect Determination Manual for the European part of USSR. Hymenoptera, 3(2):28-538.

Verma RR, Srivastava PM, 1990. Response of different varieties of apple (Malus pumila) to pest infestation. Indian Journal of Agricultural Sciences, 60(5):338-339; 1 ref.

Yasnosh VA, 1985. Parasites of the California scale. Zashchita Rastenii, No. 6:26-27

Distribution References

Borchsenius NS, 1966. A Catalogue of the Armoured Scale Insects (Diaspidoidea) of the World., Leningrad, Russia: Akademii Nauk SSR Zoologicheskogo Instituta. 449 pp.

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

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

Danzig EM, 1993. Fauna of Russia. Families Phoenicoccidae and Diaspididae., St. Petersburg, Russia: Nauka. 450 pp.

EPPO, 2021. EPPO Global database. In: EPPO Global database, Paris, France: EPPO.

Keçe A F Ç, Ulusoy M R, 2017. Armored scale insects (Hemiptera: Sternorrhyncha: Diaspididae) on ornamental plants in Adana, Turkey. Türkiye Entomoloji Dergisi. 41 (3), 333-346.

Knight A L, Christianson B A, Unruh T R, Puterka G, Glenn D M, 2001. Impacts of seasonal kaolin particle films on apple pest management. Canadian Entomologist. 133 (3), 413-428.

Kosztarab M, 1996. Scale Insects of North Eastern North America: identification, biology, and distribution., Martinsville, USA: Virginia Museum of Natural History. 650 pp.

Kosztarab M, Kozár F, 1988. Scale insects of Central Europe. Dordrecht, Netherlands: Kluwer Academic Publishers. 455 pp.

Kozár F, Brown M W, Lightner G, 1994. Spatial distribution of homopteran pests and beneficial insects in an orchard and its connection with ecological plant protection. Journal of Applied Entomology. 117 (5), 519-529. DOI:10.1111/j.1439-0418.1994.tb00769.x

Mohammad Ullah M, 1988. Major insect pests and phytophagous mites associated with deciduous orchards in Afghanistan. Tropical Pest Management. 34 (2), 215-217, 243, 247.

Nakahara S, 1982. Checklist of the Armored Scales (Homoptera: Diapididae) of the Conterminous United States., Washington, USA: USDA, Animal and Plant Health Inspection Service, Plant Protection and Quarantine. 110 pp.

New Zealand MAF Biosecurity, 2011. Pest watch: 2 November 2010 - 21 March 2011., 38 (2) 53-54.

NHM, 1962. Specimen record from the collection in the Natural History Museum (London, UK)., London, UK: Natural History Museum (London).

NHM, 1983. Specimen record from the collection in the Natural History Museum (London, UK)., London, UK: Natural History Museum (London).

Schönfeld U, 2015. Coccoidea species in Brandenburg. (Cocciden-arten in Brandenburg.). Journal für Kulturpflanzen. 67 (10), 337-341.

Sharma D R, 2011. New pest problems on fruit crops in Punjab. Journal of Insect Science (Ludhiana). 24 (3), 300-304.

Singh S S, Tiwari H C, Rai K M, 2001. Evaluation of some modern insecticides against San Jose scale, Quadraspidiotus perniciosus (Comstock) on apple. Journal of Entomological Research. 25 (1), 69-71.

Verma S C, Thapa C D, 2005. Present status of major insect-pests and diseases of apple in Chamba District and technological interventions by Krishi Vigyan Kendra, Chamba. Acta Horticulturae. 415-418.

Verma S P, Dinabandhoo C L, 2005. Armoured scales (Homoptera: Diaspididae) associated with temperate and subtropical fruit trees in Himachal Pradesh. Acta Horticulturae. 423-426.

Distribution Maps

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