Although both adults and larvae cause feeding damage, the larvae is responsible for majority of the damage. They feed on the leaf surface between veins, removing all the green material down to the lower cuticle resulting in an elongated windowpane in the leaf. Severe feeding damage came give a frosted appearance to the field. The pupal stage takes from 10 to 14 days to complete. When new adults emerge from pupation they feed briefly on grasses, before leaving the field and finding a suitable protected overwintering site.
Adults are strong, active flyers and can move some distance.
Monitoring The first sign of CLB activity in the spring is adult feeding damage on the plant foliage. While this is the first sign of adult activity, adults are not the target of control. Eggs and larvae are monitored by plant inspection since thresholds are expressed as egg and larvae numbers per plant or per stem. Examine 10 plants per location and select 1 location for every 10 acres of field. Both eggs and larvae can be found by examining the upper leaf surface.