elm sawfly

The elm sawfly (Cimbex americana) is a large insect found in North America. It is characterized by knobbed antennae, orange-tinged tarsi, and a black head and thorax, with a lighter, spotted abdomen. Its wings are smoke-brown. The larvae of the elm sawfly are yellowish or greenish-white with a dorsal black stripe and are known to defoliate elm and willow trees.1

Sawflies, in general, are a primitive group of insects within the order Hymenoptera. Adults resemble wasps but lack a constricted waist. Their larvae are caterpillar-like and possess fleshy prolegs on most body segments. The elm sawfly belongs to the Cimbicidae family of sawflies, which are large and robust with club-shaped antennae.2

While the elm sawfly itself is a defoliator, other insects can also harm elm trees. For instance, the elm leaf beetle and elm borers are beetles whose larvae bore into elm wood or whose adult and larval stages feed on elm leaves. Additionally, Dutch elm disease, a fungal disease spread by bark beetles, has significantly impacted elm populations in Europe and North America.345