Bull Pine Sawfly – Zadiprion townsendi

Bull Pine Sawfly   Scientific Name: Zadiprion townsendi Common Name:  Bull pine sawfly, conifer sawfly Appearance:  Bull pine sawflies have a thick, brown body with light banding on the upper side. It is almost 10 to 12 mm long with a pair of small feathery antennae. The females are generally larger than the males and yellow, while the males are black. During the larval stage, the worms are dark green or black with gold specks.   Host Plants or Food: Bull pine sawflies mainly feed on ponderosa pine and pinyon; however, they may occasionally feed on other pine species. Territory: Throughout North America Mode of Damage:  They act as leaf chewers and feed on the needles on the pine leaves. Habits and Life History: Bull pine sawfly feeds in groups throughout the winter season on pine trees, especially ponderosa pine. Defoliation commonly occurs in areas with sparse growth. After mating, the female sawfly cuts open a slit on the needle and inserts its eggs in there. The eggs overwinter and then hatch in the spring. The larvae actively feed on the needles until it is ready to pupate. It falls to the ground, goes underground about an inch, and forms a silk cocoon around itself, where it pupates to emerge as an adult in May or June. They produce two generations per year. Completing the entire lifecycle takes about two years.