Wheat stem maggot biology & life cycle
Overwinters as a larvae hidden inside the lower parts of the stem of wheat or other hosts. Larvae form a pupa the following spring and adults emerge in June. Eggs are laid on the leaf blades or stems on which the hatched larvae feed. The young maggots crawl down inside the leaf sheaths and tunnel inside the plant. When mature, larve pupate inside the stems. Second generation adults emerge in mid-summer and lay their eggs on wild grasses or immature volunteer grain. Larvae produced by this generation overwinter. The head of an infested plant dies and turns white while the lower stem and leaves remain green. The condition is referred to as "whiteheads" or "silvertop". In wheat, feeding occurs above the upper node.
