Drosophila suzukii (SWD) poses a threat to soft and stone fruit globally. SWD inhabits non‐crop areas adjacent to farms from where it moves into crops to cause damage. Effective IPM control strategies, considering both the crop and non‐crop area, are needed to control this economically important pest. We conducted a meta‐analysis to quantify the impacts of different non‐crop habitats around fruit farms on SWD populations, comparing abundance of SWD trapped in crop and non‐crop habitats. Overall, SWD abundance was greater in non‐crop habitats than in cropped areas and this difference was greatest in farms adjacent to woodland, or field margins containing known SWD host plants. The difference in SWD abundance between crop and non‐crop habitats was not affected by crop type but was greatest in the winter months and in conventional compared to organic farms, indicating conventional approaches can reduce relative SWD abundance. Drosophila suzukii overwinter in non‐crop habitats which provide refuge outside the cropping season. However, certain habitats support greater relative abundance of SWD than others and this is also affected by farm management. We discuss what these findings mean for effective control of SWD.

Spotted-wing Drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), is a damaging insect pest of sweet cherry fruit worldwide including in the central valley of California where it was first reported as an economic pest in spring 2009. The aim of this field-based study was to assess the relationship of Brix level and skin firmness on D. suzukii oviposition and infestation in 4 commercially important sweet cherry cultivars: Bing, Black Tartarian, Brooks, and Rainier. Results of this field study found that both higher Brix values and lower skin firmness resulted in increased fruit infestation in all varieties, highlighting the importance of these factors in host susceptibility. Other potential factors are also discussed as they relate to D. suzukii fruit infestation. Implications of these findings are discussed as well as how they might be used in future D. suzukii management in sweet cherries.

Spotted-wing Drosophila (Drosophila suzukii), an economically important invasive but widely distributed pest, has developed resistance to multiple insecticide classes, threatening its management in commercial soft fruit production. This study evaluated the synergism of piperonyl butoxide (PBO) with zeta-cypermethrin in two field-collected resistant California populations and a susceptible population with bioassays. Female flies from the two resistant populations exhibited 55-fold and 25-fold resistance, respectively, compared to the susceptible population. PBO co-application significantly enhanced insecticide efficacy in both resistant populations, with synergism ratios of 6.51 and 4.06. However, complete susceptibility at label rates of the insecticide was not restored, indicating that other resistance mechanisms may also be present in these populations. PBO–pyrethroid combinations show promise for improving field efficacy against resistant populations, though they should be integrated with insecticide rotation and other integrated pest management tactics for sustainable resistance management.

BACKGROUND: Drosophila suzukii (Matsumura) causes serious damage to soft and stone fruit globally, resulting in substantial economic losses. Due to its unique ability to oviposit in and degrade ripe fruit, management programs rely primarily on insecticides to minimize pest pressure. While insecticide resistance has been reported in D. suzukii populations, the stability of this resistance remains unknown. We assessed resistance stability to the pyrethroid insecticide zeta‐cypermethrin in a field‐collected D. suzukii population under continuous laboratory selection pressure over multiple generations and after the selection pressure was removed. We further assessed resistance stability following a population bottleneck resulting from applications of a greater concentration of the insecticide following initial laboratory selection. RESULTS: Following termination of continuous zeta‐cypermethrin laboratory selection for 20 generations, the LC ₅₀ of the field‐collected D. suzukii population remained stable for an additional 16 generations. A second field‐collected population initially selected in the laboratory then subjected to a greater insecticide concentration to create a population bottleneck then followed by continued zeta‐cypermethrin exposure after a recovery period resulted in increased resistance as indicated by LC ₅₀ values. CONCLUSION: Field derived resistance to a commonly used pyrethroid insecticide in D. suzukii can persist post‐selection and following a population bottleneck in a laboratory environment. These are the first studies to assess insecticide resistance stability in this economically important pest, and results warrant consideration for pest management programs. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.