July 1997 - Dusky birch swafly
Defoliation on white birch in the Blackduck area by the dusky-birch sawfly, Croesus latitarsus, has been reported. Its hosts are various species of birch. Larvae when fully developed are yellow-green with shades of dark black blotches in series along the sides. The larvae are gregarious and feed along the leaf margins toward the mid-ribs.