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Virginia, North Carolina change stink bug thresholds for corn

• By Dominic Reisig •

The threshold for stink bugs in corn is changing based on recent research conducted in both North Carolina and Virginia. These studies indicated that, while seedling thresholds were effective, there was evidence that the pre-tasseling and early reproductive stages threshold should be lowered.

ncsu stink bug thresholdsWe also shortened the period that stink bugs needed to be controlled from R4 to R2, since there is no evidence that brown stink bugs can cause economic yield loss (except, perhaps, at very high levels) past R2. New thresholds are listed on our website.

A major concern in lowering these thresholds is that more unnecessary spraying will take place. Unfortunately, most stink bug sprays are made without proper scouting, often applied too late to reduce economic injury (typically tank mixed with a fungicide at tasseling) and without adequate coverage near the ear zone.

These unneeded or poorly targeted sprays are wasted money to the grower and could create resistance issues in the future.

Stink bugs tend to infest field edges, so it’s easy to get excited if scouting is done with a quick trip out of and back into the pickup cab. We still anticipate that, even with these threshold modifications, most corn fields will not exceed the economic threshold if they are properly scouted.

Refer to the information on our website for our scouting recommendations. Bifenthrin is the most effective registered insecticide. Using off-label insecticides on corn is unneeded and illegal.

Dr. Dominic Reisig is professor and Extension specialist, Entomology & Plant Pathology, at North Carolina State University. He may be reached at dominic_reisig@ncsu.edu.