Lily Leaf Beetles
Monday, 07 June 2010 09:11
Lily leaf beetle adults and larvae are active, feeding on foliage of Asiatic lilies and Fritillaria in many areas. In other areas Eggs have been laid and are hatching. Monitor for the bright red beetles and also for the eggs on the undersides of the foliage. Inspect the leaves for fine tan-colored, irregular-shaped lines about one inch long. On closer examination, these tan lines will be a row of eggs. Just before hatching, these eggs turn a bright red color. When eggs are found, they can be removed and destroyed.
Lily leaf beetle (Lilioceris lilii) is known to lay its eggs and develop only on true lilies, Lilium species (Turk's cap lilies, tiger lilies, Easter lilies, Asiatic and Oriental lilies) (not daylilies), and fritillaria (Fritillaria sp). Although lilies and fritillaria are the primary hosts, lily leaf beetle also feeds, sometimes just lightly, on a number of other plants, including lily of the valley (Convallaria majalis), soloman's seal (Polygonatum sp.), bittersweet (Solanum sp.), potato (Solanum tuberosum), hollyhock (Alcea) and various hosta species. It is however, a devastating pest to true lilies.
If your customers only have a few plants in their garden, hand-picking adults and eggs can be effective. Products containing neem (Bon-Neem, Azatin), a botanical insecticide, have been shown to kill very young larvae but must be applied every five to seven days after egg hatch. Products containing the systemic imidacloprid are providing effective control applied either as a foliage spray or soil drench depending on label instructions. Imidacloprid is the active ingredient in
The University of Rhode Island (URI) Biological Control Lab is researching natural enemies of the lily leaf beetle. Small parasitic insects have been released throughout NewEngland and URI researchers hope that the insects will disperse naturally from these release sites, eventually reducing problems with the lily leaf beetle
Lisa Tewksbury, URI is continuing to track these parasitic insects by collecting the large larvae covered with excrement (brown blobs) that are found on lilies. They will dissect the larvae to look for the parasitic insects. If you or customers you know have larvae, and wouldn’t mind sending them to URI please use the following instructions to send them to Lisa at the URI Department of Plant Sciences or contact her for more information. Instructions and more information
More information on LLB
Photos: Larvae Eggs Adult Beetle
Lily Leaf Beetle Fact Sheet, UMass
University of Rhode Island Bio Control Lab (includes photos of parasitic wasp)
Evaluation of resistance to Lily Leaf Beetle in Lilium spp. Cultivars
Tina Smith, University of Massachusetts
Leanne Pundt, University of Connecticut
