Invasive beetle discovered in Minnesota

Published 8:00 pm Tuesday, July 14, 2020

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The lily leaf beetle (Lilioceris lilii), an invasive insect that feeds on lilies and fritillaries, has been found for the first time in Minnesota, according to a press release.

A resident of St. Paul first noticed an insect on an Asiatic lily and reported the find to the Minnesota Department of Agriculture. 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 as well as fritillaries. 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.

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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.

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.

“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.”

More information on lily leaf beetle can be found on the MDA website.