In Montana it was first found in Yellowstone County and the following year was detected in Yellowstone, Stillwater, and Carbon Counties. Current Montana distribution. Damage Both adults and larvae of the cereal leaf beetle feed on small grain foiliage. The larvae is the most damaging stage and the target of control measures. Life Cycle and Description Adults are the overwintering stage, moving into grain fields and feeding for about 10 days on small grain and grass foliage after they become active in the spring.
Adults prefer spring grains over winter grains.
It is important to correctly identify the adults since other beetles, common in cropland, resemble the CLB . Eggs are laid end to end singly or in groups of 2 or 3 on the upper leaf surface near the base of the leaf. Newly laid eggs are bright yellow, darkening to orange-brown and finally to black before they hatch. The larvae has a yellow body with brown head and legs . The body is protected by a layer of slimy, fecal material which makes them look like a slug.