Final report for WRGR23-004
Project Information
Integrated pest management (IPM) is a framework to consider all available tools to sustainably reduce crop damage from pests. In Washington and Oregon, which together comprise most of United States pear and apple acreage, several pests are being managed unsuccessfully due to over-use of pesticides disrupting biocontrol (pest suppression from predators). Pear orchards often apply over 10 insecticide sprays per season at a cost of $2,500 per acre while failing to prevent pear psylla damage, while apple orchardists are turning to diazinon to kill woolly apple aphid despite industry-wide desire to move away from organophosphate pesticides.
There is evidence that integrated strategies that conserve biological agents through wise timing and selection of pesticide sprays keep pear psylla and woolly apple aphid suppressed. A major challenge to adopting these strategies is a multi-year lag in establishment of biological control agents. Insecticide-based management strategies usually extirpate European earwig, a key biological control agent of both pear psylla and woolly apple aphid. This predator has low dispersal ability and will not quickly recolonize orchards once a spray program is revised for biocontrol compatibility.
We propose to support greater transition to integrated pest management in pear and apple with education and training in European earwig releases. Previous projects developed methods to collect and release European earwigs to establish populations in orchards and suppress pests. Our team will share this knowledge with educational presentations and dissemination of educational materials. We will host workshops where stakeholders can collect their own earwigs to release in orchards and report back with monitoring data. This project will reduce roadblocks to adopting integrated pest management and improve pest suppression, saving growers money and increasing their profits while reducing use of environmentally harmful pesticides with human health risks.
Objective 1: Increase knowledge of how to successfully integrate biocontrol in pear and apple pest management, especially in the role of European earwigs and how to conserve them.
- Measure increase in knowledge among at least 200 stakeholders in each of Wenatchee (year 1), and in Wenatchee, Yakima, and Hood River (year 2) regions after educational presentations.
- Increase awareness of predators and parasitoids via three newsletter articles for Tree Fruit Matters, distributing field notebooks with biocontrol pictures and facts to 700 stakeholders across the three regions, and managing a project webpage similar to Orpet et al. (2022).
Objective 2: Facilitate and train tree fruit professionals to monitor, collect, and transport earwigs to inoculate orchards lacking earwigs and increase biocontrol services.
- Document ability of at least 80 stakeholders to collect earwigs at workshops across the three regions and two years.
- Measure success of earwig releases and ability of workshop attendees to monitor earwigs with reports from each person the following year (years 2 and 3).
Objective 3: Increase the number of pear and apple acres using IPM by facilitating the documentation of outcomes and the sharing of results.
- Share at one presentation targeted to each of the three regions and via an open-access peer-reviewed article earwig data from participating stakeholders to show that the predator was established in IPM orchards.
The Pacific Northwest is the main pear and apple production region in the United States. Washington and Oregon comprise 32,000 pear acres (60% of USA pear acreage, $292 million market value) and Washington comprises 172,000 apple acres (59% of USA acreage, market value of $2.5 billion) (NASS 2022).
The most important pear pest, pear psylla, and one of the most important apple pests, woolly apple aphid, are currently unsuccessfully managed in conventional orchards due to unsustainable patterns of pesticide use. Pear orchards often apply over 10 insecticide sprays per season at a cost of $2,500 per acre while failing to prevent pest damage (DuPont et al. 2021). In contrast, orchards following organic or integrated pest management guidelines (IPM) have similar or lower populations of pear psylla in pear and woolly apple aphid in apple because spray programs permit survival of predators and parasitoids (Orpet et al. 2020, DuPont et al. 2021).
Despite its effectiveness, IPM is not widely used to its full value. Insecticides that harm predators and induce woolly apple aphid outbreaks, such as spinetoram and novaluron (targeted against the key apple and pear pest codling moth), continue to be applied despite availability pheromone mating disruption combined with chemical alternatives (Beers et al. 2016).
A major barrier to adoption of IPM in pear and apple is a lag in establishing predator populations. European earwig suppresses pear psylla (Höhn et al. 2007) and woolly apple aphid (Orpet et al. 2019), but earwigs are usually extirpated by conventional insecticides and take years to establish in orchards transitioning to IPM. European earwig has low dispersal ability, usually traveling <30 meters in a season (Orpet et al. 2019). Hence, human-assisted inoculation of orchards with earwigs would reduce pest damage and insecticide reliance, lowering barriers to adopting IPM.
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Milestones |
2023 |
2024 |
2025 |
2026 |
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Pre- award |
Growing season |
Winter |
Growing season |
Winter |
Growing season |
Winter |
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Collaborator meetings |
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Obj. 1 |
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Presentations |
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Newsletters |
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Obj. 2 |
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Workshops (Wenatchee) |
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Workshops (Yakima) |
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Workshops (Hood River) |
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Obj. 3 |
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Earwig counts (pear) |
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Earwig counts (apple) |
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Share results |
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The project will start in April 2022, when Orpet will hold an online collaborator meeting. The team will meet each year to consolidate plans. In combination with activities below, this will help members of the team to be a regional resource on biocontrol and earwigs for stakeholders.
Presentations and newsletters will increase knowledge of earwigs and how to integrate pesticides and biological control in pear and apple. Orpet will deliver presentations, distribute educational notebooks, and manage evaluation surveys. A pre-2023 growing season presentation in Wenatchee (North Central Washington Pear Day, Jan 19) will reach at least 200 stakeholders; post-2023 growing season will include at least one presentation per Wenatchee, Yakima, and Hood River of similar scope.
Workshops will be conducted at research orchards by Orpet and a grant-funded assistant to train stakeholders. We expect 20 stakeholders to attend each workshop. Collaborators will attend workshops and advertise them with their community, and Orpet will manage evaluation surveys.
Earwig counts will be collected by workshop participants the season after releases. Orpet will share results on earwig establishment and labor time to raise awareness at similar venues as the educational presentations and conferences, reaching at least 500 stakeholders in each region via presentations and newsletters articles. The project will also be described in a peer-reviewed article in the open-access Journal of Integrated Pest Management for stakeholders to refer to and for other researchers to learn from.
Cooperators
- (Researcher)
- - Producer
- (Researcher)
Education & Outreach Initiatives
(Objective 1) Increase knowledge of how to successfully integrate biocontrol in pear and apple pest management, especially in the role of European earwigs and how to conserve them
Educational presentations and newsletter articles were shared during 2023, 2024, and 2025. These activities shared information on how to integrated biological and chemical control successfully and included information on the role of European earwigs and how to conserve them.
Twenty-five presentations and six newsletter articles are described in the Educational & Outreach Activities section below. Approximately 800 notepads with biocontrol pictures and facts were distributed, mainly in the Wenatchee region, to communicate biocontrol knowledge. A project website was created (https://cahnrs.wsu.edu/tfrec-orpet/earwigs/) to house educational resources and share project outcomes.
The pre-approved WSARE evaluation was not distributed at educational presentations due to overlap with existing Washington State University extension impact evaluation activities conducted by others. Survey fatigue and low response rates limits the utility of evaluations at these events. However, some evaluation data are available indicating that presentations successfully increased knowledge of biocontrol and especially earwigs. Evaluation information was provided by Tianna DuPont and Ricardo Lima of Washington State University Extension for the following:
- Orpet, RJ. 2023. A pear study circle: phenology-based integrated pest management. Dec 13. 20-min introduction to study circle extension event in Cashmere WA, Dec 13.
- 75 attendees, 23 survey responses
- 76% reported an increase in knowledge a good or great deal
- On person wrote intention to "actively promote earwigs" in free response portion
- Beers, EH, and RJ Orpet. 2024. Woolly apple aphid IPM. North Central Washington Apple Day.
- 184 attendees, 41 survey responses
- 8 people explicitly mentioned earwigs in a free-response about what they learned from the conference, including "I need more earwigs in my orchard" and "there are free earwigs available in Wenatchee!"
- 6 people explicitly mentioned earwig monitoring or releases in a free-response about what the intend to do
- Sayles, M, and RJ Orpet. 2024. 5-min introduction to Pear IPM grower panel. North Central Washington Pear Day.
- 258 attendees, 36 survey responses
- 1 person explicitly mentioned importance of earwigs in a free-response about what they learned from the conference
(Objective 2) Facilitate and train tree fruit professionals to monitor, collect, and transport earwigs to inoculate orchards lacking earwigs and increase biocontrol services.
An earwig collection and transportation workshop was held in Wenatchee during 2023, and workshops were held in Wenatchee, Whatcom, Yakima, and Hood River during 2024. There were 9 fruit growing operations participating in the 2023 workshop and 33 in 2024 workshops. Participants saw a demonstration of the use of corrugated cardboard for earwig collection and transportation in buckets. We discussed with each attendee the philosophy behind earwig transportation within an integrated pest management program and each person received educational handouts on pesticide effects on earwigs and tips on earwig transport.
Each workshop included an evaluation survey filled out by all participants. The survey was reviewed by Washington State University IRB and determined exempt from federal regulation. Findings are described in the Project Outcomes section below. A follow-up survey was 2025 to assess actual practices changed following workshops. Results are in Figure 1. Note: the follow-up survey was not administered for Western Washington since most attendees were non-commercial and small scale and the earwig techniques were not always applicable to their situations relative to the industrial focus in other districts.
Altogether, most attendees at workshops said they intended to conduct their own collection and transportation of European earwigs after attending the workshops, but the follow-up survey indicated that fewer than half actually did. Similarly, almost everyone indicated they anticipated improving their advice/counsel and networking as a result of the workshops, and around 25 - 50% reported actually doing so the year after. We don't think that discrepancy between intentions vs. practices are a failure of the workshops, but rather that surveys only measuring intentions are naturally over-optimistic. The ability to re-survey the whole population of workshop-goers was a strength of our project. The results indicated variable reasons for not conducting earwig transportation, mainly constraints in time or a realization that the grower already had earwigs in their orchard. Among those that replied to the follow-up survey, 75% in Washington and 86% in Oregon said they would attend another earwig transportation workshop.
One challenge in the project was effort required by growers to evaluate effects of earwig transportation. Therefore, to demonstrate the effects of European earwig transportation on establishing earwig population in pear, our research team conducted releases in four commercial plots. Two of the plots were owned a by a grower who was a new collaborator and did attend any of the workshops, but was planning to transition to IPM the next year. We documented that European earwigs were elevated in release plots compared with control plots the year after releases. Almost no earwigs were found in control plots, and although few were found in release plots, it was below the abundance expected to provide significant biocontrol. This highlights an important part of the European earwig release philosophy - the goal is to re-establish European earwig populations more quickly than would be naturally possible in orchards that currently lack population and are switching to IPM programs.
Our research team also quantified the amount of time taken to conduct earwig transportation activities and materials costs. Each earwig shelter costs about 10 cents in materials. Labor to construct, deploy, and service shelters is about 2 minutes per shelter. At a labor cost of $30/hr and adding in costs of fuel and time in transit for each acre treated, the cost per acre of an earwig transportation project is <$100 when >20 earwigs can be collected per shelter and >6 acres are treated (Figure 2).
One manuscript describing the workshops, survey results, and economic data has been completing and is in review with co-authors at the time of this final report. It will be submitted to Journal of Integrated Pest Management during 2026. This will be an open-access article that growers and researchers can use to help plan earwig transportation projects. A second manuscript is being drafting describing the results of the release experiments mentioned above. Continued extension and outreach is planned with newsletter articles and presentations related to these articles.
(Objective 3) Increase the number of pear and apple acres using IPM by facilitating the documentation of outcomes and the sharing of results.
On the follow-up survey, workshop-goers were asked about the amount of acreage they used transportation on and whether they changed their spray programs.
The anticipated outcome is that people who have tried earwig transportation will increase their acreage under IPM programs. This is expected to be associated with reduced pesticide use and reduced pest damage.
On the follow-up survey, around 25% of workshop-goers reported modifying their spray programs to make them more earwig-safe. The total acreage reported that the technique was applied to was 300 acres. Around 45% of workshop-goers felt that releasing earwigs improved biological control, 45% were not sure, and 10% felt that they did not.
The project probably also had non-quantified effects on the community at large outside of the population of workshop-goers. We received several inquiries for earwigs and advice during 2025 and the project director was invited to give two presentations related to earwigs to growers in 2025. The earwig transportation project was part of a larger overall effort to encourage IPM adoption and probably increased awareness and interest.
Educational & Outreach Activities
Participation summary:
Accounting for overlap in presentation audiences across two years, it is estimated that 259 consultants and 459 growers were reached by presentations related to this project.
Presentations which included educational information on earwigs included:
- Orpet, RJ. 2025. Understanding earwigs for pest suppression. GSLong. 17 Jan. Hood River, OR.
- Orpet, RJ. 2025. Pear pest management – IPM evaluations 2024. Wilbur-Ellis. 14 Jan. Webinar.
- Orpet, RJ. 2024. Pear IPM update. Pear IPM Advisory Meeting. 25 Oct. Wenatchee, WA. 20 attendees.
- Orpet, RJ. 2024. Pear Insects Laboratory tour to Hispanic Orchard Employee Education Program. Jul 3, Wenatchee, WA. 15 attendees.
- Orpet, RJ. 2024. Tree Fruit IPM for gardens and small orchards. Kitsap Community Harvest tree fruit school series. Mar 25, Kitsap, WA (remote).
- Orpet, RJ. 2024. Aphids, earwigs, & apple IPM in 2024. Northwest Wholesale growers’ meeting. Feb 20, Wenatchee, WA.
- Orpet, RJ. 2024. Integrated pear pest management. Okanagan pear grower and consultant meeting, organized by Okanagan-Kootenay Sterile Insect Release Program. Feb 9, British Columbia, Canada (remote presentation).
- Orpet, RJ. 2024. Woolly apple aphids, earwigs, and apple IPM. Northwest Wholesale growers' meeting. Feb 1, Omak, WA.
- Hanel, A, R Orpet, R Hilton, L Nottingham, T Northfield, & R Schmidt-Jeffris. 2024. Towards an earwig-friendly IPM program in pome fruit. North Central Washington Apple Day. 284 attendees.
- Beers, EH, and RJ Orpet. 2024. Woolly apple aphid IPM. North Central Washington Apple Day. 284 attendees.
- Sayles, M. 2024. 5-min introduction to Pear IPM grower panel. North Central Washington Pear Day. 258 attendees.
- Orpet, RJ, A Hanel, R Schmidt-Jeffris, & C Adams. 2024. Sharing earwigs for inoculation biocontrol in pear and apple. Orchard Pest & Disease Management Conference. Jan 11, Portland, OR. 100 attendees.
- Orpet, RJ. 2023. A pear study circle: phenology-based integrated pest management. Dec 13. 20-min introduction to study circle extension event in Cashmere WA, Dec 13. 75 attendees.
- Orpet, RJ. 2023. Pear IPM tactics 5-min introduction to grower panel; panelist. NW Hort Expo, Dec 5. 100 attendees.
- Orpet, RJ. 2023. Pear psylla field day 2023, Aug 16. 20 attendees.
- Orpet, RJ. 2023. Pear psylla and IPM. North Central Washington Fieldman’s Association breakfast meeting, April 18. 20 attendees.
- Orpet, RJ. 2023. Pear psylla phenology and management. Decision Aid System workshop webinar, April 14. 3 attendees.
- Orpet, RJ. 2023. IPM strategy for pear psylla. Hi-Up growers meeting, Peshastin, Feb 22. 12 attendees.
- Orpet, RJ. 2023. Chemical effects on pear natural enemies and management outcomes. Northwest Wholesale Incorporated Wenatchee Growers Meeting, Wenatchee, Feb 21. 50 attendees.
- Orpet, RJ. 2023. Integrated pest management and how it works for pear psylla and mites. Okanogan Horticultural Association Annual Meeting, Feb 7. 75 attendees.
- Orpet, RJ. 2023. Pear psylla control and IPM programs. Northwest Wholesale Incorporated Omak Growers Meeting, Omak, Feb 2. 100 attendees.
- Orpet, RJ. 2023. Pear psylla integrated pest management. Northwest Wholesale Incorporated Cashmere Growers Meeting, Cashmere WA, Jan 31. 50 attendees.
- Orpet, RJ. 2023. Integrated pest management and how it works for pear psylla. 76th Annual Lake Chelan Horticultural Meeting, Chelan WA, Jan 21. 70 attendees.
- Orpet, RJ. 2023. Phenology-based integrated pear pest management step by step. North Central Washington Tree Fruit Days Pear Day, Wenatchee WA, Jan 19. 500 attendees.
- Orpet, RJ, M Sayles, C Sater, C McCullough, L Nottingham. 2023. The phenology-based pear psylla IPM program, why it's needed, and how it works. Orchard Pest and Disease Management Conference, Portland OR, Jan 11. 100 attendees.
Newsletter articles included:
- Orpet, R. Free earwigs and earwig training, Wenatchee, Yakima, Hood River, and Whatcom, 2024. Washington State University Tree Fruit Matters. Jun: https://treefruit.wsu.edu/article/free-earwigs-and-earwig-training-wenatchee-yakima-hood-river-and-whatcom-2024/
- Orpet, R. A pre-bloom pear psylla management program, 2024. Washington State University Tree Fruit Matters. Feb: https://treefruit.wsu.edu/article/a-pre-bloom-pear-psylla-management-program-2024/
- Orpet, R and M Sayles. Third-generation pear psylla outlook, August 2023. Washington State University Tree Fruit Matters. Aug: https://treefruit.wsu.edu/article/third-generation-pear-psylla-outlook-august-2023. Sent to 3,000 subscribers.
- Orpet, R. Managing second-generation pear psylla, July 2023. Washington State University Tree Fruit Matters. Jul: https://treefruit.wsu.edu/article/managing-second-generation-pear-psylla-july-2023. Sent to 3,000 subscribers.
- Catron, K. Rally the troops: free earwigs to be distributed to pome fruit growers at TFREC workshop. Washington State University Tree Fruit Matters. June: https://treefruit.wsu.edu/article/rally-the-troops-free-earwigs-to-be-distributed-to-pome-fruit-growers-at-tfrec-workshop/
- Orpet, R. Woolly apple aphid management in 2023. Washington State University Tree Fruit Matters. May: https://treefruit.wsu.edu/article/woolly-apple-aphid-management-in-2023. Sent to 3,000 subscribers.
Learning Outcomes
Project Outcomes
In 2023, nine producers, consultants, or managers were served by the Wenatchee earwig transportation workshop. All of them received earwigs to release on their tree fruit acreage. All of them reported an intention to monitor earwigs, modify their spray programs to protect earwigs, and improve their advice/counsel to others in 2024. All but one intended to collect and transport earwigs in 2024 using what they learned at the workshop.
In 2024, 33 producers, consultants, or managers were served by the earwig transportation workshops. Eleven were served in Whatcom, where the community tended to be small producers and gardeners. All but two of them intended to transport or monitor earwigs in their tree fruit. The remaining community members represented tree fruit industry in Wenatchee, Yakima, or Hood River. Of these 22 people, 100% reported an intent to monitor earwigs in 2025 and all but one intended to transport earwigs.
Figure 1 discussed above indicated that fewer people actually implemented intended practices. However, outcomes for the community members described above underestimate the full impact of the project, as attendees of educational presentations have increased their knowledge of tree fruit integrated pest management and the role of earwigs even if they did not attend the workshop.
Some of the positive comments provided on the follow-up survey included:
"Great program to transport earwigs from a pest (peach orchards) to a predator (pear)" (warehouse field staff from Wenatchee, WA)
"great idea - we are all organic in our Pears and have seen this program really change our psylla outlook. If I had a block with some issues or a neighboring block causing problems I would high invest in [this]" (grower in Wenatchee, WA)
"I learned so much I didn't know about earwigs!!" (field manager from Wenatchee, WA)
"The orchard that earwigs were released in, in '24 had considerably less psylla pressure in '25 with also an IPM focused spray program. They were easy to find in 25 beat trays early in the morning. Can't help but think they contributed to a cleaner year." (grower in Wenatchee, WA)
"Workshop was very informative, I was also able to collect earwigs from a cherry orchard and move them into my pear orchard this year" (grower/consultant is Hood River, OR)
"I think continuing to preach the value of earwigs in our pear production systems with evidence and then teaching people how to raise them would be a great course." (consultant in Hood River, OR)
A larger project with more support from researchers to treat more acres and evaluate the effects could have had a bigger lasting effect on the Wenatchee and Hood River industries. They have a big opportunity to save money by reducing insecticide use, and earwigs could help push them to make the transition. As it stands, people are talking and there is high interest in earwigs and in IPM. I hoped to help put earwig transportation into the hands of the industry as a technique, and this project documents some evidence that this has occurred. However, some continued leadership from the university/extension side would pay off I think. Recommendations for further study:
-long-term evaluation of the effects of different earwig release rates on earwig abundance and effects on pests over 3+ years, including economic analysis
-research to increase efficiency of earwig collection. The methods used here were adapted from research projects where standardization and accurate earwig quantification was needed. Growers do not need to spend that much time on that and perhaps could collect more quickly with other techniques. Establishment of a network including growers with collection sites, and organization of collection days by university/extension staff would also decrease challenges of earwig collection.