The elm zigzag sawfly, Aproceros leucopoda, recently has been detected in several midwestern states. The sawfly is from eastern Asia and is not considered a threat in its native habitat, but here it can cause severe damage. Feeding exclusively on most native and introduced elm species, the elm zigzag sawfly is a defoliator that causes damage to the leaves of the trees. Look for zig-zag chewing patterns in elm leaves and report any suspected elm zigzag sawfly infestations to the Midwest Invasive Species Network.
