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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Publications at this Location » Publication #422719
Research Project: Biological Control of Invasive Pests in Agroecosystems and Wetland, Forest and Rangeland Ecosystems in the Far Western U.S.

Location: Invasive Species and Pollinator Health

Title: Semi-natural habitat as a source of Drosophila suzukii (Diptera: Drosophilidae) and its parasitoids in California cane berry fields

Author
item Hogg, Brian
item DAANE, KENT - University Of California Berkeley

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2025
Publication Date: 10/16/2025
Citation: Hogg, B.N., Daane, K.M. 2025. Semi-natural habitat as a source of Drosophila suzukii (Diptera: Drosophilidae) and its parasitoids in California cane berry fields. Journal of Economic Entomology. 118:6. https://doi.org/10.1093/jee/toaf267.
DOI: https://doi.org/10.1093/jee/toaf267

Interpretive Summary: Although the presence of natural habitat can boost natural enemy abundance in nearby crop fields, it can also increase pest numbers in some instances. The invasive fruit fly spotted wing drosophila (SWD) attacks cultivated soft-skinned fruit such as blueberries, strawberries and raspberries, but also feeds on many wild and ornamental hosts, and may persist in natural habitats when fruit is unavailable in the crop. Natural habitats may also provide shelter for SWD or protection from insecticides. We sampled SWD numbers along transects extending from natural habitat into cane berry fields in the central coast of California, to determine whether SWD moves from natural habitat into adjacent crop fields. We examined whether the effect of natural habitat changed over time by sampling multiple times over the growing season. In spring and fall, numbers of SWD adults were higher in natural habitat and at the edge of berry fields near natural habitat, indicating that natural habitat was a refuge and source for SWD for most of the year. Moreover, proportions of female SWD were higher in berry fields in spring and fall, and increased with distance from natural habitat, suggesting that females dispersed more widely in berry fields than males. On the other hand, natural habitat may not have been a significant source of SWD in summer, when SWD numbers and proportions of females did not change along transects within berry fields.

Technical Abstract: Although the presence of semi-natural habitat can boost natural enemy abundance in crop landscapes, it can also increase pest pressure in some instances. The invasive pest spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), attacks many wild and ornamental hosts, and may persist in semi-natural habitats when fruit is unavailable in the crop. Semi-natural habitats may provide shelter for D. suzukii or refuge from insecticide applications. We sampled D. suzukii numbers along transects extending from semi-natural habitat into cane berry fields in the central coast of California, to determine whether semi-natural habitat is a source for D. suzukii in adjacent crop fields. We examined whether the effect of semi-natural habitat changed over time by sampling multiple times over the growing season. In spring and fall, numbers of D. suzukii adults were higher in semi-natural habitat and increased with proximity to semi-natural habitat in berry fields, indicating that semi-natural habitat was a refuge and source for D. suzukii for most of the year. Moreover, proportions of female D. suzukii were higher in berry fields in spring and fall, and increased with distance from semi-natural habitat, suggesting that females dispersed more widely in berry fields than males. On the other hand, semi-natural habitat may not have been a significant source of D. suzukii in summer, when D. suzukii numbers and proportions of females did not change along transects within berry fields.