Research Topics

Our lab develops IPM strategies for pests of tree fruit. Current projects focus on pear psylla (pear), leafhoppers (cherry), spotted wing drosophila (cherry), and codling moth (apple and pear). We also have initiatives related to better understanding and improving Extension and outreach.

Cherry Leafhoppers and X-Disease

Many leafhoppers are found in orchards and vineyards. Although, direct feeding injury is of low consequence, some species vector a phytoplasma born disease known simply as X-disease.  This disease is similar to other “litter cherry” diseases caused by viruses vectored by mealybugs. Immediate symptoms are small, off-color and bitter tasting cherries, but eventually the disease will kill the tree.  This is a very new issue to Washington and there has been almost no previous research on the leafhopper species that vector X disease. More information on x-disease and leafhoppers can be found here:

X-disease Factsheet

Codling Moth

Codling moth, Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae), is the most important pest of apples worldwide. IPM research over the past 3-4 decades has led to impressive improvements in the sustainability and effectiveness of management. Prior to the 1990s, this pest was managed mostly with broad-spectrum insecticide sprays; now, the primary tool is pheromone mating disruption and selective insecticide sprays timed to degree days.

Our lab is beginning a project in 2022 to help growers improve estimates of population density and injury potential using different trapping lures and mating disruption regimes. This project will test and, if necessary, establish new thresholds catered to specific lure types and mating disruption.
We are also working with the DAS team to validate current codling moth phenology models through intensive scouting and modeling. We hope to better understand the occasional discrepancies between models and trap captures with a more thorough understanding of differences between population dynamics and phenology.
Apple with codling moth entry hole
Apple with codling moth entry hole

Spotted Wing Drosophila

Spotted wing drosophila (SWD) is a worldwide pest of soft fruits; in Washington Tree Fruit, cherries are the primary target. The adults invade orchards and lay eggs in the fruit. What makes this pest uniquely dangerous is its ability to oviposit in ripening fruit (as opposed to ripe or overripe fruit like more drosophilids), possible due to it’s serrated ovipositor.  Little is known about where this pests overwinterers and non-crop hosts it uses. Our lab is using next generation sequencing and gut content analysis and determine what non-crop plants are important hosts in Washington.

SWD overview
Gut Content Analysis Grant Report

Funded Projects


  • Quantifying codling moth capture, lure plume reach, and trap area. 2022 – 2022 WA Tree Fruit Researcher Commission (Apple). Co-PIs: R.T. Curtiss, Tobin Northfield,
  • Improving Extension to Increase Adoption of IPM in Pears. 2022 – 2023, BIOAg, WSU CAHNRS, Co-PIs: Robert Orpet, WSU, Molly Sayles, WSU
  • Developing a Leafhopper Degree-day Mgmt. Program for Cherry IPM. 2022 – 2025 WA Tree Fruit Researcher Commission (Cherry). Co-PIs: Tobin Northfield, WSU, Chris Adams OSU
  • Developing a phenology-based recommendation program for pear psylla. 2020 – 2023. WSDA Specialty Crop Block / Washington Tree Fruit Research Commission. Co-PI: Vince Jones, Robert Orpet, Matt Jones
  • Insecticidal control of leafhoppers in cherries. 2020 – 2022. WA Tree Fruit Research Commission – Cherry . Co-PI: Tobin Northfield
  • Deep sequencing SWD gut contents to reveal non-crop alternative host plants. 2020 – 2022. BIOAg, WSU CAHNRS, Co-PIs: Robert Orpet, WSU and W. Rodney Cooper, USDA
  • Expanding the IPM toolbox for sustainable pear production. 2020 – 2022. USDA, Crop Protection and Pest Management, Co-PIs: Tianna DuPont WSU, Richard Hilton OSU.
  • Baseline resistance of pear psylla to Bexar (tolfenpyrad) and non-target effects. 2020 – 2021. WA State Commission on Pesticide Registration Co-PI: Tory Schmidt WTFRC
  • Improving pear pest management with integrated approaches. 2019 – 2022. WA Tree Fruit Research Commission – Pear. Co-PI: Elizabeth H. Beers WSU


  • Tactics to improve natural enemy releases in tree fruit (Apple and Pear) 20212023 WA Tree Fruit Research Commission (Apple), PI: Rebecca Schmidt-Jeffris, USDA ARS
  • Wigging out, then wigging in: earwig capture and augmentation for biocontrol. 2020 – 2023. Western SARE. Co-PI: Rebecca Schmidt-Jeffris, USDA ARS
  • Field evaluation of leafhopper controls for X disease management. 2020 – 2022. WA Tree Fruit Research Commission – Cherry. Lead: Tobin Northfield, WSU
  • Incorporating Trechnites into a psylla biocontrol program. 2019 – 2022.WA Tree Fruit Research Commission. Lead: Rebecca Schmidt-Jeffris USDA
  • Erythritol: an artificial sweetener with insecticidal properties. 2021. WA Tree Fruit Research Commission. Lead: William R. Cooper USDA