As the wheat stem elongates, maggots are usually found just above a leaf node. Infestations of Hessian fly tend to be found further up the plant as the stem elongates, because females prefer to lay eggs on newly emerged leaves. The maggots feed by scraping the stem, then sucking up the sap that oozes out of the wound. The maggots feed for 14 to 30 days. It is built from the insect ' s skin, and named for its resemblance to a seed from the flax plant.
Adults then emerge and start a new generation.
If it is too hot or cold, Hessian flies remain as maggots inside the flaxseed until the weather moderates. There are 4 to 6 generations per year of this pest in the South. Generations tend to overlap. The pest oversummers as flaxseeds in wheat stubble. The first generation in September is generally on volunteer wheat or on wild grass hosts, the most important of which is little barley.