Sawflies

Sawflies (family Tenthredinidae) are a group of insects belonging to the order Hymenoptera. Unlike many other members of their order, they do not have a constricted "waist." In agriculture, they are recognized as significant pests, as their larvae are voracious leaf-feeders capable of causing severe damage to a wide range of crops.

These insects infest a variety of plants, including fruit trees and field crops. Notable targets for infestation include apple, plum, winter oilseed rape, winter barley, fodder beet, alfalfa, garden pea, and hops. The larvae feed on the foliage, often consuming it entirely except for the veins.

The biology of sawflies follows a complete metamorphosis cycle: egg, larva, pupa, and adult. Adult females use a serrated ovipositor to cut into plant tissue, depositing eggs inside. Once the larvae emerge, they begin feeding immediately, often in groups, which leads to rapid defoliation of the host plant.

The damage caused by sawflies is primarily aesthetic and physiological. By stripping leaves, the pests disrupt photosynthesis, which weakens the plant, stunts its growth, and significantly reduces yield potential. In the case of fruit trees, they can also cause damage to developing buds and fruitlets, leading to harvest losses.

Integrated pest management (IPM) is the most effective approach for control. This includes cultural practices like tilling the soil to expose overwintering pupae, promoting natural predators, and applying targeted insecticides when larval populations reach economic threshold levels. Regular field scouting is crucial for early detection and mitigation.