Lily Leaf Beetle

The lily leaf beetle (Lilioceris lilii Scopoli) is a European insect introduced into Canada around Montreal in the 1940's. It was found damaging lily plants in Maine in 1997 and has since spread throughout much of the state.

This insect is a major pest of lilies (Lilium). It also feeds on some varieties of fritillaria and Solomon’s seal and possibly plants like lily-of-the-valley and campanula, but does not feed on daylily (Hemerocallis).

Adult lily leaf beetles overwinter in plant debris or soil, emerging in spring when lily plants begin growing. Gardeners may first comment on the beauty of the 3/8” long, bright red adult, before they realize the damage it causes. Females lay reddish orange eggs in ragged lines on the underside of lily leaves. In 7 to 10 days the eggs hatch and the larvae emerge. The larvae are about 1/4" long, plump, yellow brown to orange red and are covered with dark, slimy excrement. Adults and larvae are commonly found together devouring lily foliage. Often, they consume all the leaves leaving only bare stems. The most severe damage usually occurs from June into August.

Handpick larvae and adults of the lily leaf beetle from infested plants before severe damage occurs. If lilies are inspected regularly, the reddish eggs may be pinched off before hatching. General-purpose insecticides labeled for leaf beetle and perennial/ornamental use, should give control. Once the insect is established in an area, adult beetles continually fly about seeking food plants; repeated control applications are often necessary.

Before applying any pesticide, READ THE LABEL. Pesticides must be applied only as directed on the label to be in compliance with the law.

Websites with more information:

University of Rhode Island Lily Leaf Beetle Fact Sheet
UMass Extension Lily Leaf Beetle Fact Sheet
University of Guelph Lily Leaf Beetle Fact Sheet

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Lily Leaf Beetle