Trap captures of spotted wing drosophila (SWD) have begun increasing dramatically this week in many locations throughout NY state. However, at some sites, SWD first trap capture has not yet been reported or numbers are still very low. Populations are specific to site, year, and conditions, and populations can increase rapidly. It is critical to monitor at your location to have the best information for deciding management actions.
First trap captures were reported this week for Franklin and St. Lawrence Counties. Sustained trap captures were reported for Columbia County.
You can also be checking for fruit infestation using a salt float to detect larvae in the fruit. Instructions are available on the Cornell Fruit Resources webpage or a PDF can be downloaded at this direct link. It’s a quick field test that can be accomplished in a just a few minutes of sampling and then waiting for the larvae to emerge.
The beginning of July has been dominated by heat and storms across the Northeast. High temperatures recorded since the beginning of the month have continued to be in the upper-80s to 90s (F) in many regions. Lows have dropped only into the mid-60’s or 70’s most nights. It means phenomenally bad conditions to be out working. The good news is that this may also include fruit flies! As Julie reported on the SWD Blog in 2014, lethal temperatures for various drosophila were tested by scientists in 2004 (Kimura 2004). To test SWD’s temperature tolerance, flies were held at constant temperature in dark for a 24-hr period to determine the lethal temperature (LT) at which 25%, 50%, and 75% of the flies died. In this work, SWD died at and above 90 F.
First captures have been reported this season the following counties:
- Chenango
- Clinton
- Columbia
- Dutchess
- Essex
- Franklin
- Niagara
- St. Lawrence
- Onondaga
- Orleans
- Rensselaer
- Schuyler
- Suffolk
- Tioga
- Wayne
Weekly SWD trap captures by location across NY in 2025
Thank you to all of our collaborators for servicing SWD traps across the state!