Most Un-Wanted: Lily Leaf Beetle

August 1st, 2010

Lily Leaf Beetle Lily Leaf Beetle1 Lily Leaf Beetle2

Wanted For: an invasive species that dines on & destroys ornamental lilies, also exhibits an interesting habit of personal hygiene – covering themselves with their own excrement

Description: beetle has bright scarlet body & black legs, head, & antennae and the Larvae resemble slugs with swollen orange, brown, yellowish or even greenish bodies and black heads

Hangout: asiatic lilies

Kryptonite: Neem, Spinosad, Pyrethrins

The adult beetles stay alive throughout the winter and emerge early in the spring, when they begin looking for food and a mate. The adult females lay their eggs on the underside of lily leaves and the females produce between 250 and 450 eggs. The eggs appear in April or May and hatch within eight days.

The young larvae feed on the underside and the upper surface of lily leaves and sometimes on lily buds. This feeding period, which lasts 16 to 24 days, is the most destructive. From there, the beetles drop to the soil and pupate, emerging as adults about 16 to 22 days later & feed throughout the rest of the growing season.

And their personal hygiene leaves something to be desired: they secrete and carry their excrement on their backs. While they feed, the lily leaf beetles cover their bodies with their own excrement, giving them a grotesque appearance. It is some sort of defensive mechanism – it makes them look like a bird dropping, warding off predators and parasites.

If you only have a few plants in your garden, hand-picking adults and eggs can be effective (we prefer not to handle larvae, although there is no danger in doing so). Neem is most effective – it will repel beetles and kill young larvae, but must be applied every 5 to 7 days after the eggs hatch. Spinosad will kill the larvae.

lady bug