What has been a decades-old problem in northern Florida peppers, tomatoes and eggplants—Western flower thrips—has recently become a pest in the southern part of the state.
Many of the same lessons learned in the north, such as adhering to strict integrated pest management tactics and preserving beneficial insects, can be applied to the south, says Joe Funderburk, a University of Florida entomology professor.
“We have to quit making recommendations for just one pest,” says Funderburk, who’s based at the Institute of Agriculture and Food Sciences North Florida Research and Education Center in Quincy.
In addition, he says, pest management decisions need to be vertically integrated. The situation in the south is complicated by pockets of Western flower thrips that have grown resistant to the spinosyn class of insecticides, which includes Radiant, Success, SpinTor, Entrust and Naturalyte. These belong to the Insecticide Resistance Action Committee’s Group 5.
Dow AgroSciences, the products’ manufacturer, has taken the drastic step of requesting that the Environmental Protection Agency issue a Section 24 (c) special local needs registration in Broward and parts of Palm Beach counties. The SLN registration prohibits spinosyn use until May, at which time it will be reviewed, says Tony Weiss, Dow product technology specialist based in Brandon.
“When you look at Western flower thrips, the only effective product that was available was Radiant, so that kind of tells the story,” Weiss says. “I think over time, we’ve learned more about how to manage Western flower thrips and understand the thresholds and understand the importance of identification and finding other ways to manage it rather than just with pesticides.”
Even without this highly effective class of chemistry, growers and consultants can still manage Western flower thrips with an IPM program, says Charlie Mellinger, a certified professional crop consultant and technical director of Jupiter-based Glades Crop Care Inc.
“Joe called it vertical integration—I always thought of it as a systems approach,” Mellinger says.
A one, two punch
Western flower thrips cause damage on two fronts. The adults and immatures, or nymphs, feed on the epidermal cells of fruit, causing damage known as flecking. Adult egg-laying on tomatoes causes dimpling or halo spots.
The adults also can spread tomato spotted wilt virus, which some consider to be the most serious viral diseases of tomatoes and peppers worldwide.