Pear Sawfly
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Pear Sawfly  Adult pear saw flies are tiny, shiny black and yellow insects that resemble house flies. They emerge in late may and their eggs hatch in a week. The young larvae resemble green black ½ (1cm) slugs, older larvae are yellow and segmented. They feed for 3 to 4 weeks then pupate in soil. Second generation adults appear in late July, with larvae hatching in mid August. Susceptible Plants- Pear saw flies attacks cherries, cotoneasters, pears, and plums. A related species attacks roses. Symptoms- The larvae feed on the surface of the leaves and skeletonize them, leaving only a framework of veins. Young trees may be defoliated and eventually killed. Second generation pear sawfly larvae cause the most damage. Life Cycle- The pear sawfly passes the winter in a cocoon formed in an earthen cell 2 or 3 inches below the surface of the ground. In the late spring, shortly after the cherries have come into full leaf, the adults emerge from these cocoons. After mating, the female inserts her eggs in the leaves. The eggs hatch in seven to 11 days. The young larvae emerge from the eggs to the upper surface of the leaf and cut semicircular holes in the epidermis. The young slugs begin to eat out small pieces of the leaf, first taking only the epidermis in patches, later eating deeper in large areas into the parenchyma to the veins. The feeding period varies from two to three weeks. They them crawl or drop to the ground, burrow into it and change to the pupal stage.
the greater amount of injury, especially on young trees, which they may completely defoliate. When this second generation of pear sawfly larvae becomes fully grown, they go into the ground and remain as larvae until the following spring, when they pupate.
Prevention and Control- Spray trees with a strong stream of water to remove larvae. Biological control is a factor – this pest has a number of parasites and predators that attack it. The pear sawfly can increase rapidly in neglected or unsprayed pear trees. Insecticidal Control- When pear sawfly infestation is severe; use Bonide Rotenone Dust Biological Control- Ladybug Beetles: Hippodamia convergens
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