RALEIGH — Our laboratory recently completed a vial bioassay with brown stink bugs collected from wheat. These are the same stink bugs that move into corn. Our purpose was to see which pyrethroid was most effective in corn for brown stink bug. In small plot field studies in corn, we have not been able to distinguish one pyrethroid type from another. Based on this vial bioassay, bifenthrin was the clear winner.
The active ingredients we tested were bifenthrin, cyfluthrin (the parent compound of Baythroid XL, which is beta-cyflutrin), cypermethrin (the active ingredient in Ammo), and lambda-cyhalothrin (the active ingredient in Karate Z and Warrior II). Of the doses we tested, all stink bugs were killed at:
– 1 part per million- bifenthrin
– 25 parts per million- cyfluthrin
– 25 parts per million- cypermethrin
– 50 parts per million- lambda-cyhalothrin
In addition, at the highest labeled rate of bifenthrin, you can apply at 3x or more active ingredient compared to other pyrethroids. This supports other state recommendations for bifenthrin as the pyrethroid of choice to manage brown stink bug (for example, see the GA field corn recommendation here on page 57).
Be sure to work with your aerial applicator to ensure good coverage. Your insecticide will only work if it contacts the stink bugs, which often hide underneath leaves and between the ear folds and the stem. Thresholds are listed in this previous article.
— Dr. Dominic Reisig
Associate Professor and Extension Specialist
Entomology and Plant Pathology – NC State University
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