Invasive Insect Lily Leaf Beetle Discovered for the First Time in Minnesota

St. Paul, MN: The lily leaf beetle (Lilioceris lilii), an invasive insect that feeds on lilies and fritillaries, has been found for the first time in Minnesota.

A resident of St. Paul first noticed an insect on an Asiatic lily and reported the find to the Minnesota Department of Agriculture (MDA). MDA staff then inspected the area and was able to find an adult lily leaf beetle.

The beetle is native to Europe and Asia and is currently found in Canada, the northeastern United States, and the states of Washington and Wisconsin. The larvae causes significant damage to true lilies (Lilium spp.) as well as fritillaries (Fritillaria spp.). It is reported that adult beetles occasionally feed on other plants including hollyhocks, hostas, lily of the valley, potato, and Solomon's seal. Lily leaf beetles do not cause damage to daylilies, canna lilies, or calla lilies.

"This insect is a major concern for gardeners and homeowners with lilies," said Angie Ambourn, Supervisor of the MDA's Pest Detection Unit. "Both lily leaf beetle adults and larvae chew irregular holes and notches in lily leaves, stems, and developing buds, but larvae cause the most damage to plants and can completely defoliate plants and destroy flowers."

Lily leaf beetles are very distinctive looking. The adults are bright red beetles. The eggs are reddish and laid in lines on the undersides of leaves. Bumpy, black larvae can also be found on the undersides of leaves. The larvae cover themselves with their own excrement, likely to protect themselves from predators. (See photos below)

Since this is the first reported discovery of lily leaf beetle in Minnesota, the MDA would like to better understand where this insect may be in the state and how big of an issue this is to homeowners. Residents can report suspected lily leaf beetles to the MDA's Arrest the Pest line at arrest.the.pest@state.mn.us or 1-888-545-6684. If possible, please include clear photos.