Skip to main content Skip to navigation

Year 2 of pheno-IPM for pear psylla management: it worked, 2023

A project out of the WSU Pear Insects Lab is in Year 2 of tracking outcomes in Wenatchee Valley conventionally managed pear orchards and pear orchards following new guidelines that integrate selective biocontrol-safe sprays with phenology-based timings and cultural tactics. These new guidelines are abbreviated “Pheno-IPM” because they use a pear psylla Phenology model that predicts occurrences of life stages and generations on a degree-day scale to help time multiple tactics in an (I)ntegrated (P)est (M)anagement program. Biocontrol is important in pheno-IPM, so the program focuses on well-timed narrow-spectrum spray options that let beneficials build up.

Review of spring, summer, and fall

Across 2022 and 2023, similar pest patterns occurred at the seven pairs of orchards monitored. In spring of both years, first-generation pear psylla counts were similar for pheno-IPM and conventional spray programs (data are in a June article of Fruit Matters). In summer of both years, pheno-IPM had more second-generation pear psylla. In 2022, this is when pheno-IPM orchards could sustain pear psylla damage. In 2023, pear psylla abundance was much lower across the Wenatchee Valley, and little damage tended to occur (a July article in Fruit Matters defined management programs and shows outcomes in summer). While biocontrol agents were building up under the pheno-IPM program, they were practically eliminated in conventional orchards using broad-spectrum sprays. Due to biocontrol, close to harvest the third generation of pear psylla remained low in pheno-IPM orchards while increasing in conventional orchards. Well-timed rains reduced the potential for honeydew damage in 2023, but conventional orchards on balance still suffered more pear damage than pheno-IPM orchards this year (Table 1).

The pheno-IPM orchards last year had similar outcomes on average as conventional ones on the project, and this year pheno-IPM had less pear damage. It is important to recognize that there is variation in outcomes under both types of management. Some pheno-IPM orchards did not always have a great outcome, but the same can be said of conventional orchards. The Pear Insects Lab will be working hard in the future to continue to study the stability and effectiveness of different pear pest management strategies.

What is happening in pear orchards now?

After harvest, pear psylla adults have skyrocketed in conventional orchards, like last year. The Pear Insects Lab is going to continue scouting pear orchards through winter this year to better understand movement of this pear psylla and how the very large populations in conventional orchards may contribute to high areawide pest pressure in the Wenatchee Valley.

More data and upcoming opportunities

You can follow along with scouting updates, observe the full range of monitoring, and keep informed on upcoming events on the e-mail newsletter Pear Entomology Weekly. The latest issue has fall data for 2023 pear psylla, mites, and biocontrol agents. You can get these pear newsletters automatically by e-mail by subscribing. Pear Entomology Weekly is expected to continue in 2024 and will be used to share scouting data from Wenatchee, Yakima, and Hood River in addition to pheno-IPM guidelines. On December 13, there will be a public event for growers and consultants to discuss pheno-IPM with researchers; please RSVP if you’d like to join.

line graph comparing conventional and pheno-IPM in 2023
Figure 1. Pear psylla adults per beat tray at conventional and pheno-IPM orchards in 2023. After harvest, pear psylla adults have skyrocketed in conventional orchards, like last year.


Table 1. Honeydew damage from pear psylla

Honeydew damage from pear psylla represented by percentage of US1-rated fruit based on what WSU entomologists saw in the field at orchards at seven locations following conventional, pheno-IPM, or organic management. Damage ratings were taken within a week of commercial harvest at each location.

Locations Management Bartlett preharvest
Bartlett preharvest
% US1
Anjou preharvest
Anjou preharvest
% US1
Rock Island Conventional 8/14 100 9/11 90
Rock Island Pheno-IPM 8/14 100 9/11 99
Monitor Conventional 8/15 99 9/12 100
Monitor Pheno-IPM 8/22 100 9/12 100
Cashmere Conventional 8/22 99 9/19 96
Cashmere Pheno-IPM 8/15 99 9/05 100
Cashmere Organic 8/22 100 9/19 97
Dryden Conventional 8/23 100 9/21 99
Dryden Pheno-IPM 8/23 95 9/21 97
Dryden Organic 8/23 97 9/13 100
Peshastin Conventional 8/31 100 9/21 100
Peshastin Pheno-IPM 8/31 100 9/21 100
Peshastin Organic 8/31 100 9/21 100
HWY 97 Conventional 8/24 99 9/28 98
HWY 97 Pheno-IPM 8/24 100 9/07 100
Leavenworth Conventional 8/31 96 9/28 82
Leavenworth Pheno-IPM 8/31 100 9/14 100
Average Conventional n/a 99.0 n/a 95.0
Average Pheno-IPM n/a 99.1 n/a 99.4
Average Organic n/a 99.0 n/a 99.0


Robert Orpet professional photo

Robert Orpet

Funding and acknowledgements

  • Thank you Fresh Pear Committee and Processed Pear Committee for funds.
  • Thank you Tianna DuPont for comments on the first draft of this article.

Additional information

  • Learn about pear psylla management:
  • In previous Fruit Matters, the Pear Insects Lab outlined the IPM program and outcomes in 2023:
    • March Issue – prebloom pesticide programs were defined
    • April Issue – reviewed spring pear psylla biology and where to find pear psylla degree-days
    • May Issue – pre-bloom pear psylla in IPM and conventional Wenatchee Valley pears were similar
    • June Issue (a) – spring pear psylla in IPM and conventional Wenatchee Valley were similar
    • June Issue (b) – explanation of earwig transit into pear orchards to help stop pear psylla
    • July Issue – defined summer philosophy for pear IPM and showed, as expected, quantified more second-generation pear psylla in IPM and organic orchards vs. conventional.
    • August Issue – an outlook on third-generation pear psylla and biocontrol action, 2023


Fruit Matters articles may only be republished with prior author permission © Washington State University. Reprint articles with permission must include: Originally published by Washington State Tree Fruit Extension Fruit Matters at and a link to the original article.

Use pesticides with care. Apply them only to plants, animals, or sites listed on the labels. When mixing and applying pesticides, follow all label precautions to protect yourself and others around you. It is a violation of the law to disregard label directions. If pesticides are spilled on skin or clothing, remove clothing and wash skin thoroughly. Store pesticides in their original containers and keep them out of the reach of children, pets, and livestock.

YOU ARE REQUIRED BY LAW TO FOLLOW THE LABEL. It is a legal document. Always read the label before using any pesticide. You, the grower, are responsible for safe pesticide use. Trade (brand) names are provided for your reference only. No discrimination is intended, and other pesticides with the same active ingredient may be suitable. No endorsement is implied.

Washington State University