July 2014 – Page 3 – Spotted Wing Drosophila

The first two female SWD of the 2014 growing season were captured over the week of July 3 to 9 in traps monitored by Faruque Zaman, Long Island Horticultural Research and Extension Center, Suffolk County Cornell Cooperative Extension in a yeast-baited trap at a ripening raspberry location in eastern Long Island.

On July 9, examination of 40 fruits found 2 SWD-infested raspberries with egg-laying sites at that location. The raspberry field is surrounded by grapes on one side and blackberries on the other side; no adjacent forest boundaries. No SWD have been captured in traps placed in other locations in Suffolk County, including blueberry, blackberry, grape, forest and a second raspberry site and no fruit infestation was found in raspberries collected from the second site.

At this time the SWD population appears to be very low. Therefore, cultural practices such as harvesting fruits frequently and removing rotten fruits from the field will help keep the SWD population down. Also, remove alternate weed hosts, pokeweed and bittersweet nightshade, from the area before these weeds develop fruit. SWD populations and damage can increase dramatically with favorable weather and susceptible ripe fruits. Insecticide applications are necessary when SWD populations are high. Insecticide control requires frequent applications (5-7 day interval), so delay onset of spraying until sustained captures occur in your area to maximize the utility of the applied materials.

Two female spotted wing Drosophila captured in traps on Long Island on July 9, 2014.

Tiny threads of the SWD egg breathing tubes indicate where an egg was laid in a raspberry. Two eggs were found in 40 fruits examined. — Tiny threads of the SWD egg breathing tubes indicate where an egg was laid in a raspberry. Two eggs were found in 40 fruits examined on July 9, 2014.

Reports have come in from Southwest Michigan by Rufus Isaacs, Michigan State University, and Middlesex County in Connecticut by Rich Cowles, CT Agricultural Experiment Station of first catch of SWD. As of today, no one in the NY monitoring network has reported trap catch of SWD. Although the catch in Michigan was of several adults, the report from CT was of a single male.

Because this finding in central CT is of a single adult, don't interpret this as meaning that ripe fruit is immediately at risk. What we have observed in the past is that we can capture a lone adult here or there, but it isn't until we get sustained captures in traps set in susceptible fruit plantings that growers are at risk of infestation.

On Long Island, fruit samples contained no evidence of infestation this week nor were any SWD caught in traps set there in Suffolk County. No other reports of SWD caught in traps have come in from NY. But do stay tuned. The number of other fruit flies being caught in my traps in Wayne County, Sodus Bay area, jumped significantly this week from around 150 per trap last week to almost 1000 other fruit flies per trap.

Although the heat has been unbearable in places...let's cheer, because SWD adults are intolerant of temperatures much above 90F.

Month: July 2014

First find in NY – Suffolk Co.

First finds outside NY 2