Monitoring for Drosophila suzukii in southern highbush blueberries using perimeter and central traps and evaluation of tools for management

The spotted wing drosophila (SWD) Drosophila suzukii (Matsumura) has become a serious threat to Florida’s blueberry industry.  Females oviposit under the skin of ripening fruit where larvae develop, rendering fruit unmarketable.  Our hypothesis is that SWD moves into cultivated blueberries from surrounding wooded areas.  To investigate SWD migration into blueberry plantings a survey was conducted on 10 blueberry farms in 7 Florida counties from Polk in south-central to Suwannee in the north.  Six plastic cup traps baited with apple cider vinegar and dish soap were set at each site along the perimeter and within the center of the field.  Traps were serviced weekly.  Survey results showed higher captures in perimeter traps than traps that were centrally located potentially suggesting that SWD immigrates into fields from surrounding habitats.  In order to identify management tools for SWD, a field-based bioassay was conducted to evaluate the effectiveness of reduced-risk pesticides versus grower standards on SWD mortality and reproduction.  Experiment was RCBD with 6 treatments and 4 replicates.  The treatments included 3 commonly used conventional pesticides, Malathion®, Mustang®, and, Danitol® at a high and low application rate, 1 reduced-risk pesticide, Delegate® and a non-treated control.  Efficacy results showed that the reduced-risk chemical is as effective as conventional tools and therefore provides growers with additional tools for managing SWD populations.