The spotted wing drosophila, an invasive species which can cause damage to fruit crops, has been identified in Chautauqua County.
The discovery of the SWD occurred on Aug. 7 in traps set in a red raspberry planting in Chautauqua County by Cornell Cooperative Extension employees Virginia Carlberg and Elizabeth Burgeson.
The SWD is native to sections of Asia, and was discovered on the West Coast in 2008 and 2009, before spreading throughout the contiguous states, especially in locations where fruit production is high.
Adult SWD flies resemble common vinegar flies and sometimes are referred to as small fruit flies. Common vinegar flies can be found in the kitchen, around compost piles or on fallen, decaying and rotting fruit in the garden. Vinegar flies are attracted to the smell of yeast, wine, or rotting or fermenting fruit. In the garden, vinegar flies prefer rotting fruit that has fallen from the plant. Unlike common vinegar flies, SWD flies prefer ripe to over-ripe fruit on the plant.
With the discovery of SWD in Chautauqua, the pest has now been discovered in all terminal counties of New York, joining Niagara, Clinton and Suffolk counties, and fruit infestation is being reported throughout the Hudson Valley and in portions of the Finger Lakes and the Ontario Plains.
Although it is late in the growing season, there are still many fruit crops which are harvested throughout September and October which could be affected by the pest. Although the SWD which were discovered in Chautauqua County were limited to two male flies, the potential discovery of other SWD in the county still looms.
According to CCE, traps baited with an apple cider vinegar drowning solution plus an ampule containing a yeast bait floating in the cider vinegar have proven most successful in capturing adult SWD. Traps should be checked once per week, adding fresh vinegar drowning solution and fresh yeast bait. Those who would like instructions on how to make their own traps can visit www.fruit.cornell.edu/spottedwing/monitoring.html.
Additionally, fruit can be inspected for evidence of larval feeding. Small holes in berries made by the larvae may leak juice when the berry is gently squeezed. Fruits with multiple drupes, such as raspberries, may be too fragile to gently squeeze, so instead CCE recommends checking to see if a red juice stain appears on the berry receptacle when picked, as this could indicate an SWD-affected fruit.