Pear Psylla

Common: Pear Psylla

Scientific: Cacopsylla pyricola

Crop Hosts: Pear

Identification and Life Cycle: The pear psylla overwinters as the adult under bark of trees. In the spring, the females deposit orange-yellow eggs in cracks in the bark or around the buds. They hatch in 2 weeks to a month and small, wingless yellow nymphs suck sap from the underside of the leaf. These nymphs take about a month to mature and pupate. Three to five generations can occur in a season.

Geographical Distribution: Spread from Pacific Coast to all pear-growing states.

Damage and Treatment: The leaves on heavily infested trees turn brown and often drop off. The fruit drops or is undersized and is of poor quality. The leaves and fruit can also be covered with a black fungus that feeds on the honeydew produced by the larvae. Psylla also transmit pear decline disease, which can cause death of the tree.

Treatment should be made when insect populations and/or damage levels reach economic thresholds. Refer to local University Extension Pest Management Guidelines for specific state thresholds.