Cereal leaf beetle biology & life cycle
The adults overwinter in clusters in sheltered places including under field trash, tree bark, and inside rolled leaves. The adults become active in the spring when the temperature reaches 10 to 15C and are active for about 6 weeks. Eggs are laid either in pairs or singularly, and are fixed half-way up the plant on the upper surfaces of the grass blades by adhesive. The larvae emerge 5 days later and begin feeding. The larvae pass through 4 instars, then pupate and emerge as adults, feeding for 2 more weeks before seeking shelter for winter. There is 1 generation per year and the entire life cycle takes about 45 days. Both the adults and larvae feed on the leaves of the plant, chewing out long strips between the veins. The adults will eat through the entire leaf, whereas the larvae only eat the top surface of the leaf, leaving a thin membrane. The larvae attack the flag leaf starting at the tip and move down the leaf. With extensive damage, the leaves turn whitish in colour, giving the appearance similar to frost damage. Yield damages can be high.
