Ag Alert: Cereal Leaf Beetles Causing Damage


The following Ag Alert was issued this week by Montana State University:

Be on the lookout for the larvae of cereal leaf beetle (CLB) damaging the leaves of small grains, especially the newest growth. CLB larvae are less than ¼” long with yellow coloring, but they usually appear brown due to being coated with a droplet of feces / mucous. This insect prefers spring-seeded small grains, especially barley, wheat and oats. The larvae feed on the upper leaf surface, chewing part way through the leaf. CLB-damaged foliage has pale streaks and patches that run parallel to the veins of the leaf blades. Heavy feeding can cause the entire leaf to turn white, causing fields to appear frosted.

CLB adults are about 1/4″ long and 1/16″ wide with a metallic blue head and forewings. The legs are yellow, and the “neck” and thorax are orange-red. Adult CLB chew entirely through the leaf. However, adults are less damaging than the larvae. CLB have one generation per year and overwinter as adults. The following resources offer further information on monitoring and control products for CLB:

Threshold information:

General CLB information:


Ruth O’Neill, MSU PSPP Research Associate

Kevin Wanner, MSU PSPP Crop Extension Entomologist

Source:  Montana State University

Posted by Haylie Shipp


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