Insecticide Notes

Thrips control: Thrips are difficult to control in almost any situation, but they are particularly difficult to control in crops grown in high tunnels because some of the more effective insecticides for thrips control are not allowed in greenhouses or high tunnels. In outdoor crops, products that provide fairly effective thrips control are Radiant (spinetoram), Assail (acetamiprid), and Movento (spirotetramat), but these three products are not allowed for use in high tunnels. Pyrethroids such as Baythroid (beta-cyfluthrin) and Brigade (bifenthrin) are allowed in high tunnels and can provide some control of thrips, but they are restricted use products that can be applied only by certified applicators. Other options for thrips control that are restricted-use products are Vydate, which can be used on peppers and cucurbits, and Lannate (methomyl), which can be used on peppers, tomatoes, and most cucurbits. Exirel (cyantraniliprole) is allowed for use on peppers and tomatoes grown to maturity in high tunnels, but it provides only suppression, not control, of thrips. Once a thrips population is large and causing damage, then biological control is not a realistic option, but growers who have thrips problems every year should consider a biocontrol program at the start of the new season next year, using Orius bugs or predatory mites obtained from a commercial insectary.

Japanese beetles are starting to show up in abundance in raspberries and sweet corn as well as in peaches, apples, and other crops and in landscape plants. Damage by Japanese beetle is best prevented by insecticide applications directed at the first beetles to invade an area, before they send out messages to other beetles to aggregate. Some of the most effective products have been around for a long time: carbaryl (Sevin and others) and pyrethrins plus PBO (EverGreen Pro and others). If traps are used to remove beetles from an area, they should be set up at a distance away from the crop rather than adjacent to the crop because they can attract many beetles in to the area around the trap.

Colorado potato beetle: There are recent reports from Ohio farms that pyrethroids are no longer providing adequate control of Colorado potato beetles (CPB). Pyrethroids include Warrior, Baythroid, Brigade, Mustang Maxx, Asana, and Pounce. There are several newer insecticides that are effective for control of CPB populations, but most of these are best at killing the larvae rather than the adults of CPB. Products that provide good control of larvae are Agri-Mek (abamectin), Radiant (spinetoram), Coragen (chlorantraniliprole), Rimon (novaluron), and azadirachtin products such as Aza-Direct and Neemix. Among somewhat older insecticides, the neonicotinoids are still effective at most locations; these are listed in the table below. The neonicotinoids are generally more effective by soil application, which provide true systemic control, whereas application by foliar sprays provides translaminar control but not true systemic control throughout the plant. Some of the neonicotinoids are allowed only for soil applications, some for only foliar sprays, and some for either method. If used for soil application, usually at planting time, then later foliar applications are not allowed.

-Celeste Welty, Extension Entomologist

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