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Clearance sought for insecticide to help control invasive stink bug

Entomologists in the mid-Atlantic states are still honing their pesticide recommendations so fruit growers will be prepared to battle the brown marmorated stink bug this season.
 

While they think growers will be able to handle the bug early in the season with existing labeled insecticides, they see a potential protection gap when fruit is nearly ripe and pressure is intense. At that time they need an effective insecticide with a short preharvest interval (PHI). They think that have a candidate in dinotefuran.
 

Dr. Chris Bergh, an entomologist at Virginia Tech, said that the Virginia Department of Agriculture and Consumer Services plans to petition the Environmental Protection Agency in April for a Section 18 emergency use permit for use of dinotefuran (Venom, Scorpion) on pome and stone fruits. Bergh is part of a team of university and USDA entomologists working to combat this aggressive new invasive stink bug species. They hope to have EPA’s approval by late August, when fruit harvest and stink bug populations are both peaking.
 

Dinotefuran has labels for application to grapes and some vegetables, for which the PHI is one day, Bergh said. The insecticide is used by tree fruit growers in Asia. The entomologists plan to ask EPA for a three-day PHI. The emergency label would apply in seven states hard-hit by the stink bug last year—Delaware, Maryland, New Jersey, North Carolina, Pennsylvania, Virginia, and West Virginia.
Bergh is preparing the petition, while entomologists and Department of Agriculture representatives from the participating states are submitting data and letters in support.
 

Dinotefuran is a neonicotinoid insecticide marketed by Valent BioSciences as Venom and by Gowan as Scorpion. It was developed by Mitsui Chemicals and registered in Japan in 2002. In the United States, EPA has given it status as an organophosphate alternative and a reduced risk insecticide.
 

Entomologists in the U.S. don’t have a long history with brown marmorated stink bug, which had been gradually increasing in numbers and the damage it does, but emerged last year as a serious problem, damaging almost half the peaches in Pennsylvania.
 

“We don’t have much field data to support recommendations for season-long management of brown marmorated stink bug,” Bergh said. “Growers will have to do whatever it takes in 2011, and we hope to know much more by the end of this season so we can refine our recommendations.”
 

He’s working with five growers in Virginia, testing various insecticide protocols and using attractant-baited traps to monitor stink bug populations. Laboratory bioassays have determined that some insecticides appear to work better than others. “Growers will have to mix and match them through the season,” he said, “while trying to avoid killing beneficial insects, protecting pollinators and maintaining control of the other insect pests of tree fruits.” Bergh and other entomologists in the mid-Atlantic region will be working closely with chemical companies to evaluate the effectiveness of various products and seasonal programs targeting the stink bug in 2011.
 

The list of labeled insecticides that show promise includes endosulfan, some of the pyrethroids, some of the neonicotinoids, and methomyl. Disadvantages of some of these are long pre-harvest intervals, long reentry intervals, short residual activity, and/or toxicity to beneficial insects. Those with long PHIs are only useful earlier in the season.
 

It is not yet known how quickly the stink bug populations will build this year. In some areas where high populations clustered around buildings seeking overwintering protection, they could be present in high numbers early in the season. “We may need to begin targeting brown marmorated stink bug shortly after the crop is set,” Bergh said.
 

Having an effective insecticide for use during the late summer and fall peach and apple ripening period will help growers, many of whom experienced high losses last year. But suppressing them in the orchards will not likely have a large effect on the stink bug population as a whole, Bergh said. Besides fruits and vegetables, the stink bug is known to feed on field and sweet corn, soybeans, and some woodlot and ornamental trees—some 300 host plants identified so far. Fruit farms are small islands in a large sea, so there is little potential to drive down the overall population with late season insecticide applications.
 

On the benefit side, it is not just fruit growers fighting this bug. They are in league with other farmers and homeowners, for which this insect has become a nuisance if not an economic scourge.