WSU Tree Fruit Research & Extension Center

Pear Entomology

Monday, March 25, 2019



Lacewing - Chrysoperla spp.

Lacewing Gallery

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Lacewings are important beneficial predators in the pear orchard. Eggs are laid on the ends of stalks, arranged in V-shaped rows. The stalks keep the young from cannibalizing their brethren upon hatching. The larvæ are voracious eaters, equipped with tusklike clampers and capable of rapid movement. Each larva will eat 200 or more pests or pest eggs during their 2-3 week development. After attaining sufficient bulk, they fold into a prepupal position and spin a tough fibrous cocoon. The adults emerge after 7-10 days, and may survive up to six weeks depending on local conditions.



Anthocorid Gallery

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Anthocorids, also known as Pirate Bugs, are abundant predators in pear orchards. They are polyphagous, willing to dine on psylla eggs and nymphs, aphids, thrips, young scales, and spider mites. They are not too dainty to try human flesh, either, and can inflict a painful bite. Anthocorids will occasionally probe plant tissue with their beaks, but this does not appear to cause damage.
These predators overwinter as adults in protected crevices. In the spring, the females lay eggs on leaves or buds. The larvæ are a vivid red-orange color. There are five larval instars and three generations per year.



Spider Gallery

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All spiders are predatory, which makes them excellent biological control agents. The spiders pictured here were all found in pear orchards. Some spiders build webs, others scuttle about and chase down their prey.
Spiders, like mites and scorpions, have eight legs. They generally have eight eyes, and their cheliceræ are modified as poison-injecting fangs. Although some spiders do not construct webs, all possess spinnerets and can make silk.
Apparently, spider diversity is such that an arachnologist needs to dissect the genitals of a particular individual in order to identify the species. As with most of the animals pictured on this site, these spiders are still alive and were released after their photo session. Needless to say, their genitals were not dissected (by us, anyway) and their special identities remain tantalizingly mysterious.



Mirid Gallery

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Campyloma verbasci
is a generalist predator of pear orchard pests. It eats pear psylla as well as mites and aphids. It is also known to cause damage to apples. Adults and nymphs are predacious, but may feed on fruit (causing cosmetic damage to skin of fruit) if available prey are reduced to very low numbers. Campyloma is commonly known as a Mullein Plant Bug, and can be found in most pome fruit growing regions of the northern U.S. and southern Canada.

Deræocoris laricicola
are generalist predators of plant-feeding insects and mites. The nymphs are light-to-mottled gray and oblong. The adults are dark and thick-shelled, with coppery or creamy highlights on the wing-covers. They do not have ocelli. Their name means "thick-hided."


Predatory Mites

Predatory Mite Gallery

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Typhlodromus occidentalis
The Western Predatory Mite is an important control agent of pest mites. It is white, slightly flattened, and pear-shaped, and moves at high speed. It is a benefactor of pears, plums, apples, peaches and cherries. The eggs are pear-shaped and translucent. The larvæ are six-legged but all other stages have eight legs. T. occidentalis feeds on tetranychid mites, blister mites, rust mites, European red mites, and even other beneficials when phytophagous prey is scarce.

T. occidentalis is highly susceptible to permethrin, methomyl, and esfenvalerate. Refer to Insecticide Selectivity Guide in Beers, E.H., Brunner, J.F., Willett, M.J., and Warner, G.M. (Eds.) (1993) Orchard Pest Management: A Resource Book for the Pacific Northwest, page 226 for more information.


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