Comparing apples and oranges (and blueberries and grapes): fruit type affects development and cold susceptibility of immature Drosophila suzukii (Diptera: Drosophilidae)

Abstract

AbstractDrosophila suzukii Matsumura (Diptera: Drosophilidae) is a cosmopolitan polyphagous pest on unripe soft-skinned fruits. We sought to determine (1) temperature treatments that could be used to kill immature D. suzukii in fruit or packaging and (2) whether development on different fruits led to differences in cold tolerance of immature D. suzukii. We reared animals from egg on a banana-based laboratory diet and diets made of apple (Malus domestica Borkhausen; Rosaceae), blueberry (Vaccinium Linnaeus; Ericaceae), cherry (Prunus avium Linnaeus; Rosaceae), grape (Vitis Linnaeus; Vitaceae), orange (Citrus × sinensis (Linnaeus) Osbeck; Rutaceae), raspberry (Rubus Linnaeus; Rosaceae), or strawberry (Fragaria × ananassa Duchesne; Rosaceae) homogenate in agar and measured development time, adult body size, and cold tolerance. Diet type had complex effects on development time; in particular, D. suzukii reared on apple-based or blueberry-based diets developed more slowly to a smaller adult body size than those on other diets. Cold exposure killed eggs and both first and second instars. Survival of 24 hours at +4 °C by feeding third instars was lowest in blueberry and cherry. Five days at +0.6 °C killed all feeding third instars; this treatment is likely sufficient for targeting D. suzukii in fruit. Two hours at −5 °C or −6 °C killed all wandering third instars and pupae; this exposure could be sufficient for sanitation of packaging.