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New Phenology-based Psylla Management Information

by Louis Nottingham, WSU Entomology. March 4, 2022.

As temperatures warm and the snow melts, it is time to think about pear psylla management. In warmer areas like Oregon and southern Washington, psylla are already back in the orchards and laying eggs. In central and northern WA, psylla will move into orchards once the snow melts.

IPM strategies for pear psylla provide optimal season-long control by utilizing selective sprays and cultural strategies to suppress psylla while conserving natural enemies. If you have ever wondered why psylla control falls off toward the end of the season, it is likely due to a lack of natural enemies from too many broad-spectrum sprays. This is why we encourage the use of selective management approaches, such as kaolin clay, insect growth regulators (IGRs), organic insecticides, and cultural techniques like tree washing and summer pruning.

In order to help you choose the right approach for your orchard and better understand the development of pear psylla in your region, WSU has created a pear psylla degree day model and associated management strategies. Visit the new page Phenology Based Pear Psylla Integrated Pest Management for the model and strategies. The website is a work in progress and subject to change as we continue to perform experiments and refine the conventional and organic management strategies.


Louis Nottingham

Assistant Professor, Entomology

Washington State University

540-798-2044 (cell)

Washington State University