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Summer pear psylla management, 2023

Written by Robert Orpet, WSU, 5/27/2023

Spring Leads to Summer

The Pear Insects Lab at WSU has been testing integrated pest management guideline for pear since 2022 with the goal of cheaper and better pear psylla control. Figure 1 shows similar conventional vs. integrated management outcomes in spring 2022 and 2023. This year, first generation pear psylla was about 4 times less abundant than last year, and natural enemy populations in integrated orchards are growing more quickly than last year too. With lower pear psylla and more natural enemies than last year, the integrated program looks to be on track for success going into summer.

Graphs comparing natural enemies and stages Spring 2022 and Spring 2023
Figure 1. Mean pear psylla adults per tray, eggs per fruit cluster, nymphs per fruit cluster, and natural enemies of pear psylla (Campylomma, Deraeocoris, Trechnites, ladybugs, and lacewings) per tray at 7-8 conventional, 7-8 phenology-IPM program, and 3 organic Wenatchee region pear orchards in 2022 and 2023. Insect illustrations by T Kent.


Summer, 2023

In June 2023, the second generation of pear psylla is just starting. Summerform adult numbers are increasing, and they are starting to lay eggs. Higher numbers of pear psylla are expected in integrated vs. conventional orchards during this generation. However, if predator and parasitoid populations build, integrated orchards will probably be less sticky than conventional orchards by harvest time.

We have an online two-page summary of the integrated management guidelines that makes use of the pear psylla phenology model (Figure 2). The integrated guidelines involve selective sprays targeted towards the most vulnerable points of the pear psylla lifecycle and cultural tactics like tree washing and summer pruning. Selective codling moth sprays and miticide options are included in the guidelines so pear psylla’s natural enemies remain safe. To follow along with outcomes of this in 2023 and receive free pear psylla degree-day updates like in Figure 2, you can subscribe to Pear Entomology Weekly by e-mailing Robert Orpet.

graphs comparing life stages and locations
Figure 2. Pear psylla degree-day estimations for June 3, 2023. The filled-in portions show current degree-days and unfilled curves show future trajectory through the middle of the second pear psylla generation. We can see that second generation adults are predicted to be just starting in most regions. To get free weekly updates like this alongside actual scouting data, sign up for Pear Entomology Weekly by e-mailing Robert Orpet­­ or visit the public Decision Aid System page.


Looking ahead to Fall 2023

When things go well in an integrated program and biocontrol agents have a vibrant community, pear psylla will practically disappear during their third generation going into harvest. If that doesn’t happen, additional sprays and cultural tactics for the third generation can be timed with the help of the phenology model. I will review third-generation pear psylla outcomes and management guidelines for 2023 in a future issue of Tree Fruit Matters.


Robert Orpet professional photo

Robert Orpet

Funding and acknowledgements

Thank you Fresh Pear Committee and Processed Pear Committee in addition to WSDA for pear orchard research and Western SARE Project #WRGR23-004 for funds supporting related to earwig workshops.

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