Clouds of false chinch bugs have recently been reported in some, but not all, winter canola fields in Kansas and Oklahoma, said Mike Stamm, K-State Research and Extension canola breeder.

Because of abnormally dry weather, false chinch bugs have infested winter canola fields earlier than expected, Stamm reported.

“High numbers of false chinch bugs are often observed on canola plants at ripening, after yield potential has been determined. Once thought to be a non-factor, false chinch bugs have caused some yield loss this spring considering the current growth stage of the crop,” he said.

These insects are first found in the dead plant material (fall growth) on the soil surface, and that is where they lay their eggs, he said. As temperatures warm, activity increases and the insects begin to swarm in “clouds” around and on canola plants, he said.

False chinch bugs feed by sucking sap from plants, the K-State canola breeder said. Damage will include aborted flowers and pods, plants stripped of leaves and stunting, he explained.

How heavy does the infestation have to be before an insecticide treatment is justified?

“The Great Plains Canola Production Handbook lists thresholds at 5 to 10 per head at flowering and 10 to 20 per head at early pod fill. Because false chinch bugs swarm when distributed, it may be hard to count numbers per head.

It also is acceptable to consider the thresholds as 20 to 30 per plant at flowering and 40 to 50 per plant at early pod fill,” Stamm said.   

False chinch bugs are most active when the weather is warm and sunny, so avoid spraying on cool and cloudy days, he added. “It is recommended to spray close to evening to minimize the impact on beneficial insects. Scout thoroughly because hot pockets may occur in the field. A heavy rain also can dramatically slow the activity of false chinch bug,” he said.

False chinch bugs can be hard to control so it is important to use enough spray volume to get adequate coverage. For best control with aerial applications, five gallons per acre is recommended, he said.

For effective insecticides, consult the Great Plains Canola Production Handbook at: www.ksre.ksu.edu/library/crpsl2/mf2734.pdf.