Imported Willow Leaf Beetle: Plagiodera versicolora

Coleoptera: Chrysomelidae

Identification
• Elm leaf beetle adults are ¹/₄" long, yellow to green beetles with 3 black stripes. (a)
• Elm leaf beetle larvae are up to ¹/₄" long, black, and spiny with a broad yellow stripe down the back. (b)
• Imported willow leaf beetle adults are ³/₁₆" long and metallic dark blue. (c)
• Imported willow leaf beetle larvae are up to ¹/₄" long, black, and spiny. (d)

Damage
• The adults eat holes in the leaves.
• The larvae feed on the leaf underside, leaving the upperside whitish, which dries and turns brown.
• Elm leaf beetle feeds heaviest on Siberian and American elms.
• Willow leaf beetle feeds on many willow species.

Management
• Chinese elm is less susceptible to elm leaf beetle.
• Bacterial insecticides are effective against the larvae.
• Chemical insecticides are effective against both larvae and adults.