Identification

• Adult lily leaf beetles are ¼ to 3/8 inch long. Their bodies are bright red and their legs, head, antennae and undersides are black. Lily leaf beetles lay reddish-orange eggs in irregular lines on the undersides of leaves. Larvae are sluglike in shape with black heads. Their swollen bodies are slimy and usually covered with feces. Pupae are florescent orange and are found in the soil.
  
  

Lifecycle

• Adults overwinter in the soil and break through in early spring to feed on foliage. By late spring, they lay eggs, usually on the undersides of leaves. Eggs hatch in anywhere from four to eight days as sluglike larvae. The larvae feed and pile their excrement on their backs as a defense mechanism. The larval stage lasts for 16 to 24 days. Larvae then drop to the soil to pupate. Adult beetles emerge 16 to 22 days later and feed until fall when they dig into the soil to overwinter until the next spring.
  
  

Damage

• These bright-red pests primarily feed on true lilies, such as tiger lilies and Easter lilies. They also feed on fritillaria, hollyhock, potatoes, lily of the valley, Solomon's seal, bittersweet and some hosta species. They are only devastating to true lilies. Adults feed primarily on foliage, but the larvae do the most damage. They begin feeding on the undersides on leaves but eventually move to the tops of leaves and the buds.
  
  

Control

• If you only have a few infested plants, experts at the Maine Department of Agriculture recommend handpicking the beetles. They recommend putting a light cloth under the plant so you can see any beetles that fall off and dispose of them. Wiping the leaves' undersides removes any eggs there and handpick larvae off the plant. If you have a large number of lilies and handpicking is impractical, there are useful pesticides. Products containing neem, imidacloprid or spinosad are effective.