We have received reports of false chinch bug populations in canola this week. Heavily infested canola fields will sometimes appear drought stressed, but closer inspection reveals that false chinch bugs are the culprits for the wilting plants (Figure 1). Although false chinch bugs are normally not an issue in canola, very large populations do have the potential to reduce yield (Figure 2).
False chinch bugs are relatively small at 1/8th to 1/6th of an inch long. They are slender insects that are grayish-brown in color with clear wings that are folded over their bodies. False chinch bugs feed on plants using piercing-sucking mouthparts and are commonly observed in large aggregations. A large population of these insects can result in rapid wilting and leaf dieback in plants. The false chinch bugs are able to feed on a wide variety of plants including those in the mustard family, which includes canola.
Populations of false chinch bug are normally much worse following wet, cool springs. Such weather encourages the growth of weedy hosts and allows for rapid population increases. The false chinch bugs will move into crops during hot-dry periods due to the drying down of weedy hosts. Most of the injury to canola occurs during flowering and early pod fill. The thresholds for false chinch bugs are an average of 5-10 per flowering raceme and 10-20 on racemes during early pod set. Once pods are filled, the false chinch bugs do not represent as much of a threat and damage is rarely observed.
If false chinch bug populations are above threshold, consider using a foliar insecticide with the active ingredients of either bifenthrin, deltamethrin, lambda cyhalothrin or gamma cyhalothrin.