Beginning in 2011 we began efforts to study the newly invasive insects including spotted wing drosophila in small fruit, stone fruit and grape varieties.
The spotted wing drosophila (SWD), Drosophila suzukii, was first observed in NY in 2011 beginning in late August. The following year it was first captured in mid-July in 2012 and in 2013 it was found in the Northeast considerably earlier, on the 10th of June along a wooded edge in western Mass. It was then captured in apple cider vinegar (ACV) traps baited with a yeast solution in WNY on 11th of June (Loeb), in the southern and mid-Hudson Valley on the 17th (Urlich) and 21st of June (O’Connell) respectively. On the 3rd of July, adults SWD were observed in traps placed along the border and interior of a small fruit patch in southern Orange County of the raspberry variety ‘Prelude’, in which we also found 2 of 25 fruit which we sampled infested with eggs. The brambles had been on a two-week SWD preventative program with applications made twice-weekly. Yet on the same farm in a nearby block of untreated sweet cherry, 14 of 20 or 70% fruit sampled were infested with a total of 44 eggs. Drosophila larva has not yet been observed in fruit, indicating the relatively early stage of infestation we are in early ripening cherry and raspberry. In 2012, very low population levels of SWD led to very high levels of fruit injury, which lead us to now recommend to growers with SWD in the region to begin pest management programs for this insect. As we are not completely certain that SWD is the causal agent we will continue observe fruit to access the adult emergence for species confirmation. Yet the find of eggs in pre-harvested and sound fruit is a strong indication of the kind of damage SWD is capable of.
We are advising that agricultural producers of stone and small fruit should pay strict attention to cherries, brambles and blueberries, monitoring fruit closely during the early stages of color and ripening while monitoring traps daily for the presence of this pest. As these commodities enter the 7-day pre-ripening period they are at greatest risk. Low levels of fly presence in traps may signify relatively high levels of fruit infestation potential in these commodities.