Seasonal Monitoring forDrosophila suzukii(Diptera: Drosophilidae) in California Commercial Raspberries

Abstract

Native to Southeast Asia, Drosophila suzukii (Matsumura) prefer to oviposit on ripe fruit and have become an important pest of California raspberries (Rubus idaeus L.) since their detection in Santa Cruz County, CA, in 2008. Preliminary management guidelines included D. suzukii monitoring recommendations, though there was little available information on seasonal occurrence and potential lures for use in raspberries. To address this issue, we trapped adult D. suzukii weekly for 2 yr (including both spring and fall harvests) in multiple raspberry varieties using apple cider vinegar and a yeast-sugar-water mixture as liquid lures, and measured fruit infestation when commercially ripe fruit were available. D. suzukii pressure as measured by larval infestation and adult trap captures was higher during the fall raspberry harvest season. The yeast lure captured significantly more D. suzukii during the fall harvest than the apple cider vinegar, and while both lures tended to capture more females than males, this varied by month of the year and was more pronounced for the yeast lure. Trap captures from each lure correlated well to one another, and often exhibited significant correlation to larval infestation. However, during all seasons and under both conventional and organic management, worrisome outliers were present (high larval infestation with low trap captures) that call into question the reliability of using the systems presented here as a basis for management decisions at this time.

Influences of blackberry margins on population dynamics of Drosophila suzukii and grape infestation in adjacent vineyards

“…The sex ratio of D. suzukii flies shifted towards male‐biased and back to female‐biased captures throughout the season, which is partly in line with previous studies from other regions reporting a skewed sex ratio (Haviland et al, ; Rossi‐Stacconi et al, ; Tait et al, ). The female‐biased sex ratio particularly at the beginning and the end of the year may be related to a higher winter survival or longevity of females (Hamby et al, ; Thistlewood et al, ; Zerulla et al, ). During grape ripeness (period 3), the sex ratio switched towards a higher proportion of males in traps but not in vacuum captures (Supporting Information A4) of BB sites and was male‐biased at all sites in period 4.…”

Economic Impact of the Introduction and Establishment of Drosophila suzukii on Sweet Cherry Production in Switzerland

“…While adult captures are only a poor indicator of actual crop infestation risk [22] and thus do not replace the more laborious fruit checks, traps provide early warning of fly activity and insight into the temporal variation of D. suzukii population dynamics. Ongoing research efforts towards developing modelling tools that describe and forecast D. suzukii populations will improve future management practices by predicting pest pressure independent of trap captures and samples of infested fruit [1,23,24].…”

The influence of temperature and photoperiod on the reproductive diapause and cold tolerance of spotted‐wing drosophila, Drosophila suzukii

“…Improvements in monitoring infestations or predictive modeling of D. suzukii phenology can help to optimize the use of insecticides by targeting insecticide applications during critical reproductive periods (Coop, ; Wiman et al., ). Whereas there is abundant work tracking adult flight activity and larval infestations during the growing season (Hamby et al., ; Harris et al., ; Burrack et al., ; Lee et al., ; Mazzetto et al., ), knowledge regarding D. suzukii overwintering habits and reproductive diapause is limited. A better understanding of environmental cues involved in the induction of reproductive diapause and termination would contribute to a more targeted management of this serious pest insect.…”