''Cacopsylla pyricola'', commonly known as the pear sucker, is a

true bug Hemiptera (; ) is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from to around ...

in the family

Psyllidae Psyllidae, the jumping plant lice or psyllids, are a family of small plant-feeding insects that tend to be very host-specific, i.e. each plant-louse species only feeds on one plant species (monophagous) or feeds on a few closely related plants ( ...

and is a pest of pear trees (''

Pyrus Pears are fruits produced and consumed around the world, growing on a tree and harvested in the Northern Hemisphere in late summer into October. The pear tree and shrub are a species of genus ''Pyrus'' , in the family Rosaceae, bearing the po ...

''). It originated in Europe, was introduced to the United States in the early nineteenth century and spread across the country in the next century.

Description

The eggs are tiny, stalked, oval, and cream to yellow, darkening before they hatch. The first

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

nymphs are yellowish or pinkish and flattened, but later instars are greenish to dark brown, with distinctive red eyes and developing wing buds. The edges of the buds bear three to five knobbed bristles. The nymphs are largely immobile and tend to be found on the underside of leaves. In summer the adults are a fairly pale colour but in winter they are reddish-brown to black, the transparent wings being dusky. These psylla rest with their wings folded roof-like over their abdomens.

Distribution

''Cacopsylla pyricola'' is native to Europe but was introduced into the eastern United States with nursery stock in the early 1800s; it had spread to the fruit-growing regions of the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...

by the early 1900s. Along with the

codling moth The codling moth (''Cydia pomonella'') is a member of the Lepidopteran family Tortricidae. They are major pests to agricultural crops, mainly fruits such as apples and pears. Because the larvae are not able to feed on leaves, they are highly d ...

(''Cydia pomonella''), it is considered one of the most important pest of pears in the United States. Host plants are restricted to pear and

quince The quince (; ''Cydonia oblonga'') is the sole member of the genus ''Cydonia'' in the Malinae subtribe (which also contains apples and pears, among other fruits) of the Rosaceae family (biology), family. It is a deciduous tree that bears hard ...

Life cycle

Adult ''C. pyricola'' overwinter on the bark or twigs of a pear tree, or on other trees and shrubs near pear orchards. In the spring, the female lays eggs on twigs and expanding shoots of host trees, attaching them by means of short stalks on their ventral surfaces. On hatching, the

nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are typ ...

feed on the buds and flowers of the host tree, inserting their mouthparts and sucking out the sap. Later in the year, the eggs are laid beside the veins on the upper surface of leaves. The nymphs pass through five

s before becoming adult in a few weeks. There may be up to six generations each year and numbers of insects can build up fast. The nymphs produce copious honeydew which attracts

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22 ...

flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyly, monophyletic lineage within the ...

s and other insects.

References

{{Authority control Psyllidae Hemiptera of Europe Hemiptera of North America Insects described in 1848