Pear psylla is a pest that produces an abundance of honeydew, allowing a sooty fungus to grow on the fruit. It causes fruit russet and serious infestations that can stunt, defoliate, and kill trees.

For region-specific information, please contact your local Giving Grove partner. If you would like more information like this sent straight to your inbox, consider subscribing to The Serving, The Giving Grove’s quarterly newsletter.

Appearance:

  • All life stages have two conspicuous red eyes.

  • Eggs are shaped like grains of rice and are attached to the host by a small protrusion extending from the rounded end. Eggs are creamy white when laid but turn yellow to orange as they develop towards hatching.

Damage:

  • Fruit russet: honeydew produced by the nymphs drips or runs on the fruit, and causes dark russet blotches or streaks.

  • Psylla shock: stunts and defoliates tress, causing the fruit to drop.

  • Pear psylla feeding can transmit a mycoplasma organism through its saliva, causing a disease called pear decline. Diseased trees may decline slowly or suddenly die.

  • Pear decline has varying effects on the trees depending on variety, rootstock, quality of the growing site, and pear psylla numbers.

Control & Management:

  • There are many naturally occurring predators and parasites of pear psylla including green lacewings, brown lacewings, earwig, and minute pirate bugs.

  • A late winter dormant oil application (just before or at bud break) can effectively suffocate pear psylla eggs.

  • Two holistic sprays (Neem, Liquid Fish, Effective Microbes) prior to bloom, followed by two additional holistic sprays after petal fall, may help control this pest.

  • An application of refined kaolin clay may help control this pest.

  • Limit fertilizers. Apply only enough nitrogen fertilizer to achieve adequate fruit set and good fruit size.

  • Prune trees moderately each year, rather than lightly for a few years and then heavily to correct tree size and shape.

  • Pruning off water sprouts or suckers (late June to early July) growing from scaffold limbs through the center of the trees not only removes tender foliage that psylla feed on but also allows sprays to penetrate better.

Sources: WSU Tree Fruit Research & Extension Center, UC-IPM, Penn State Extension, Patrick L. Byers, Horticulture Specialist, and Michael Phillips, “The Holistic Orchard”