Extension > Garden > Diagnose a problem > What insect is this? > Trees and shrubs > Caterpillars, maggots, grubs, and similar immature insects - Under 1 inch long > Willow sawfly

Willow sawfly

Nematus ventralis

Mark H. Brown

Description: Up to 3/4 inch long. Black heads with black or green-black bodies and large yellow spots along the sides.

Where/When: Prefers willows but will also rarely feed on poplar. Present May to June and again in July through the end of the summer.

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