''Pseudaulacaspis pentagona'', the white peach scale
[ or mulberry scale, is a species of armoured scale insect in the family ]Diaspididae
Diaspididae is the largest family of scale insects with over 2650 described species in around 400 genera. As with all scale insects, the female produces a waxy protective scale beneath which it feeds on its host plant. Diaspidid scales are far mo ...
.[
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Description
The adult female insect is up to in length. The soft yellow body is concealed under a roughly circular, whitish test
Test(s), testing, or TEST may refer to:
* Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities
Arts and entertainment
* ''Test'' (2013 film), an American film
* ''Test'' (2014 film) ...
with a yellowish-brown off-centre spot (this is the exuviae
In biology, exuviae are the remains of an exoskeleton and related structures that are left after ecdysozoans (including insects, crustaceans and arachnids) have molted. The exuviae of an animal can be important to biologists as they can often be ...
or shed skins of the last two nymphal moults). Males are concealed under whitish, felted, elongated oval tests with yellowish spots at one end; sometimes many males will accumulate in one area, covering the bark and looking like snow. Mature males have no mouthparts but have wings and seek out females, while mature females do not have wings and remain permanently in one place.[
]
Distribution
''Pseudaulacaspis pentagona'' is native to eastern Asia but has been accidentally introduced into many other warm and temperate parts of the world. In Europe, it was first detected in Italy in the nineteenth century and is now additionally found in Azerbaijan, Bulgaria, France, Georgia, Germany, Greece, Hungary, Macedonia, Malta, Montenegro, Netherlands, Portugal, Russia, Serbia, Spain, Sweden, Switzerland, Turkey and Ukraine. In the twenty-first century it has been spreading northwards, perhaps because of climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
, but is restricted to greenhouse
A greenhouse is a structure that is designed to regulate the temperature and humidity of the environment inside. There are different types of greenhouses, but they all have large areas covered with transparent materials that let sunlight pass an ...
s in cooler climates such as Sweden.
Hosts
''Pseudaulacaspis pentagona'' is polyphagous
Feeding is the process by which organisms, typically animals, obtain food. Terminology often uses either the suffixes -vore, -vory, or -vorous from Latin ''vorare'', meaning "to devour", or -phage, -phagy, or -phagous from Greek φαγε ...
, meaning that it has many plant hosts. It is particularly a pest of fruit trees such as peach, plum, apricot, cherry, currant, grape, pawpaw, fig, mulberry, apple, pear, kiwi fruit and walnut. It also infests various ornamental plants, including ''Sophora
''Sophora'' is a genus of about 45 species of small trees and shrubs in the pea family Fabaceae. The species have a pantropical distribution. The generic name is derived from ''sophera'', an Arabic name for a pea-flowered tree.
The genus formerl ...
'', ''Sorbus
''Sorbus'' is a genus of over 100 species of trees and shrubs in the rose family, Rosaceae. Species of ''Sorbus'' ('' s.str.'') are commonly known as rowan or mountain-ash. The genus used to include species commonly known as whitebeam, cheque ...
'', ''Syringa
''Syringa'' is a genus of 12 currently recognized species of flowering plant, flowering woody plants in the olive family or Oleaceae called lilacs. These lilacs are native to woodland and scrub from southeastern Europe to eastern Asia, and wid ...
'', ''Catalpa
''Catalpa'' (, ), commonly also called catawba, is a genus of flowering plants in the family Bignoniaceae, native to warm temperate and subtropical regions of North America, the Caribbean, and East Asia.
Description
Most ''Catalpa'' are decidu ...
'', ''Euonymus
''Euonymus'' is a genus of flowering plants in the staff vine family Celastraceae. Common names vary widely among different species and between different English-speaking countries, but include spindle (or spindle tree), burning-bush, strawb ...
'', '' Philadelphus'' and ''Paulownia
''Paulownia'' ( ) is a genus of seven to 17 species of hardwood trees (depending on taxonomic authority) in the family Paulowniaceae, the order Lamiales. The genus and family are native to east Asia and are widespread across China. The genus, o ...
''.
Life cycle
Mature females lay 100 to 150 eggs, the number largely depending on the food plant. The eggs hatch after three or four days; those destined to be males are orange while female eggs are white. The newly hatched first instar
An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...
nymphs
A nymph (; ; sometimes spelled nymphe) is a minor female nature deity in ancient Greek folklore. Distinct from other Greek goddesses, nymphs are generally regarded as personifications of nature; they are typically tied to a specific place, land ...
are mobile and disperse to other parts of the plant. Males have five instars while females have three; the later instars are immobile, sinking their mouthparts into the plant tissues to extract sap. There may be up to four generations each year. In the United States, a generation is completed in about 38 days in summer and about 85 days in winter. In cold climates, adult females survive the winter even when the temperature falls as low as . Dispersal to new locations may occur when nymphs are blown away or adhere to birds or flying insects; and also occurs with the transport of nursery stock.[
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References
Further reading
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{{Taxonbar, from=Q6773594
Fauna of East Asia
Insects described in 1886
Diaspidini