Brownheaded Sawfly – Tomostethus multicinctus

Brownheaded Sawfly   Scientific Name:  Tomostethus multicinctus Common Name:  Brownheaded sawfly, brownheaded ash sawfly Appearance:  Adult Brownheaded sawfly is a black-coloured insect with a greenish larva. The larva ranges in size from 14 to 20 mm long and features some banding on its body. The females have a saw-like structure on their abdomen, thus their name. Host Plants or Food: Brownheaded sawflies primarily feed on ash trees, especially red, white, and green ash trees. Territory: Throughout North America, Eastern USA Mode of Damage:  The larva is a leaf chewer and chews minute holes in the middle of the foliage. As it grows, it starts feeding more on the leaves such that only the veins are left at the end. Habits and Life History: Brownheaded sawfly is a wasp-like insect commonly found on ash trees. The female sawflies cut slits on the margins of the leaves and lay eggs in clusters. The eggs hatch into the larva, which feeds on the foliage until it is ready for pupation. Once the larvae are fully grown, it sheds their skin and falls to the ground. The skin stays attached to the leaves while the larvae drop to the soil. The larvae form a cocoon around themselves in early spring and pupate throughout the winter until they become adults in June. They produce only one generation per year.