A Spotted Wing Drosphophila Trapping Study in the Small Fruit and Grapes Plots and a Woodlot at Piketon, Ohio

Spotted Wing Drosphophila (SWD), Drosophila suzukii, has been found in small fruits, such as blackberries, raspberries and strawberries in 24 counties in Ohio.  This invasive pest attacks healthy fruits and can cause devastating crop losses.  One key aspect of SWD management is early detection since the economic threshold is one SWD (male or female).  It is important for researcher and growers to know where SWDs overwinters and when it first emerges in a mixed fruit planting with woods nearby.  The research farm at OSU South Centers fits this criterion perfectly.  There are plantings of blackberries, grapes, high tunnel raspberries, and plasticulture strawberries, and a wooded area.  A comprehensive SWD trapping study was carried out in 2014 on our research farm.  Multiple traps made out of clear 32 oz. deli cups baited with apple cider vinegar (and a drop of dish soap) were placed in each area of interest.  Traps were first placed in the woods on April 3, 2014, in the strawberry plot on May 7 in the blackberry plot on June 16, in the raspberry patch on June 16, and in the vineyard on August 30, 2014.  Traps were changed and checked on a weekly basis.   No SWDs were caught before August 14 on our research farm.  Once the first SWD was caught in the woods on August 14, more SWDs were found in blackberry and raspberry plots at the same time.  No SWDs were found in the plasticulture strawberry plot.  Only a small number of SWDs were caught in the blackberry plot after the initial catch since there were only limited amount of fruits present.  More SWDs were caught in the high tunnel raspberry plot with the highest number of catches on October 30.  Only a small number of SWDs were caught in our vineyard with the high number on October 30.  The largest number of SWDs was caught in the woods among all plots with the highest catches on November 13.  It is likely that a lot of SWDs overwinter in the woods.  These SWDs in the woods could be a potential threat to fruit patches nearby.  It is still too early to tell if reducing SWDs in the woods can lead to significant reduction of SWDs in the fruit plots nearby.