False Chinch Bugs in Sorghum, 2016

This article was first published by Dr. Tom Royer in E-Pest Alert, Aug. 8, 2016

Tom A. Royer, Extension Entomology Specialist

I have received several reports of false chinch bug infesting sorghum heads. As sorghum begins to head, it is important to make sure your crop is not being damaged by this insect. This insect injures plants by sucking the liquid in developing seeds when they are in

False chinchbug

False chinchbug

the milk stage. It has a life span of about 40 days (from egg hatch through adult).

Description: False chinch bug adults measure about 1/8-inch-long, are dirty gray, with brown or black  markings. Nymphs are ash-gray with brown-white mottling on the back and red mottling on the abdomen. 

Bucket sampling

Bucket sampling

 

 

Sampling: Sorghum heads must be examined to determine the need for control of panicle-feeding bugs. The shake bucket/baggie method of scouting works well for sampling fields. Carefully move to a plant without disturbing it, quickly shake the head into the bucket or plastic bag, and shake it vigorously. Count all false chinch bugs that fall into the bucket or garbage bag. Adult bugs will fly out of the bucket, so be prepared to count “flying” bugs. Inspect at least 1 head per acre of field (minimum 30 samples) and continue scouting sorghum until the head has reached soft dough. 

Control Decisions: False chinch bugs are not likely to cause economic injury when sorghum matures past the milk stage, so treatment for false chinch bugs after milk stage is not likely to provide economic benefit. Before milk stage, treat when scouting indicates more than 140 false chinch bugs per head. If maturity is variable, look to see where most of the false chinch bugs are located. If they are feeding on heads with seed past the soft dough stage, you may not need to treat a field. See CR-7170, Management of Sorghum Insects, or E-832, OSU Extension Agents’ Handbook of Insect, Plant disease and Weed Control for current recommendations.

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