How to Manage Pests

Pests in Gardens and Landscapes

Pear psylla—Psylla pyricola

Identification

Adult psylla are small (up to 0.10 inch long) and hold their transparent wings like a roof over their dark brown to reddish brown bodies when at rest. A dark spot on the top middle edge of both wings helps distinguish pear psylla from other psyllids.

Life cycle

Pear psylla adults overwinter in sheltered places in the bark or under the ground. Eggs are tiny, elongated, and yellow and are barely visible without a hand lens. They are laid on or near fruit spurs starting in late January or early February. As buds open, females lay eggs along midribs and petioles of developing leaves or in stems and leaves of blossoms. Nymphs pass through five instars, four of which are almost completely encased in honeydew. When first hatched, the tiny nymphs are yellow with red eyes and black antennae. The third stage is yellowish green and the fourth greenish brown. The fifth instar, called the hardshell stage, is dark with prominent wing pads.

Damage

Psylla inject into foliage a toxin that can cause blackening and burning. Nymphs also cause the production of honeydew on fruit and foliage, making them sticky and black with sooty mold. Vegetative growth may be stunted or entire trees defoliated. Pear psylla also transmit pear decline disease.

Solutions

Oil sprays applied during the dormant season will kill many overwintering adults. A second dormant treatment applied just before bloom can be considered where populations have been high.

Pear psylla adult
Pear psylla adult

Sooty mold on fruit
Sooty mold on fruit

Typical leaf damage
Typical leaf damage


Statewide IPM Program, Agriculture and Natural Resources, University of California
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