Earwig Transportation Workshop

Web Form for 2024 Workshop RSVP (click here)

Free earwigs and trainings on earwig mass-collection are available during summer 2024. Check the table below for a summary of locations. To receive detailed information and help us plan ahead, please RSVP using the web form linked above. This project is supported by Western SARE (Project #WRGR23-004).

Why earwigs?

Earwigs are present and suppress pests when other predators are not. Specialist parasitoids and other predators may have multiple generations and lag behind pest populations that they must grow on. However, earwigs are omnivores, so they won’t starve when any particular pest population is low, and they have very low dispersal ability. A combination of “resident” earwigs, which capable of decreasing pest population growth, and other natural enemies, which can knock down larger pest populations, creates a community capable of keeping pest populations stable and low.

Releasing earwigs into orchards results in fewer woolly apple aphids (Orpet et al. 2019) and fewer pear psylla (Höhn et al. 2007). We’ve also found no evidence that apples or pears are damaged by earwigs in the field. They just feed on fruit that has already been damaged, often by mechanical injury or cracking. We have video evidence that earwigs kill woolly apple aphids.

Benefiting from earwig transit

Methods are proven to monitor earwigs, transport them, and use them to suppress pests (Höhn et al. 2007, Orpet et al. 2019).

1. Will my orchard benefit from an earwig release? If your orchard already has a big earwig population, there is not much benefit from adding more. Ideal sites for earwig releases are orchards recently switching to organic or integrated management.
2. Will earwigs survive after I release them? Spray programs are probably the most important factor affecting earwig survival in Pacific Northwest orchards. We have a one-page summary table of pesticide safety to earwigs in our handout Orchard Pesticide Safety For Earwigs. The new phenology-based management guidelines for pear psylla are compatible with earwigs.
3. How many earwigs, where, and how long until I see benefits? If your released earwigs survive, a new generation of earwigs should lead to reduced pests the year after releases. The earwig population will spread about 30 meters per year. At some times of the year in some locations we can find >50 earwigs per cardboard shelter. Finding at least 5 per shelter is a good amount associated with biocontrol of pests. Releasing around 100 earwigs per tree in a low density orchard or 100 earwigs every 15′ in a high-density trellised block is the target for this workshop. At that rate, about 1,000 earwigs will cover an acre of orchard.

Resources

Orchard Pesticide Safety For Earwigs

Guide To Earwig Transportation

References

Beers, EH, NJ Mills, PW Shearer, DR Horton, ER Milickzy, KG Amarasekare, LM Gontijo. 2016. Nontarget effects of orchard pesticides on natural enemies: Lessons from the field and laboratory. Biological Control 102: 44–52. https://doi.org/10.1016/j.biocontrol.2016.04.010

Crumb, S. E., P. M. Eide, and A. E. Bonn. 1941. The European earwig. USDA Tech. Bull. 766: 76. https://naldc.nal.usda.gov/download/CAT86200761/pdf

Höhn, H, A Lahusen, R Eder, T Ackermann, L Franck, HU Höpli, J Samietz. 2007. Régulation du psylle du poirier Résultats et observations de 2002 à 2006 en Suisse alémanique. Revue suisse Vitic Arboric Hortic 39: 169–176. https://www.researchgate.net/publication/284761529_Regulation_du_psylle_du_poirier

Piñol, J., Espadaler, X., Pérez, N., Beven, K., 2009. Testing a new model of aphid abun- dance with sedentary and non-sedentary predators. Ecol. Model. 220, 2469–2480. https://doi.org/10.1016/j.ecolmodel.2009.06.031.

Orpet, RJ, JR Goldberger, DW Crowder, VP Jones. 2019. Field evidence and grower perceptions on the roles of an omnivore, European earwig, in apple orchards. Biological Control 132: 189–198. https://doi.org/10.1016/j.biocontrol.2019.02.011

Orpet, RJ, DW Crowder, VP Jones. 2019. Biology and Management of European Earwig in Orchards and Vineyards. Journal of Integrated Pest Management 10: https://doi.org/10.1093/jipm/pmz019