Posted on 7/25/2016 by Brent Adams
If you grow Oriental lilies in your flower garden here in New England, then you are probably familiar with the Scarlet Lily Beetle (Lilioceris lilii) which, if left untreated, will consume the leaves, buds, and flowers, leaving a bare (ugly) stalk, not the lush green foliage you desire to see.
While the adult insect will eat the leaves, most destruction of the plants is caused by the larval stage of the insect. You should check your plants frequently and early in the spring. Adults overwinter in the soil and the female will lay about 450 eggs. The underside of leaves is where egg masses may be found. Recognizing the yellow, brown, or orange larvae may not be easy, as they pile their excrement on top of themselves. Prior to entering the soil to pupate, the larvae eat for 16 to 24 days. The adult will hatch 16 to 24 days after pupation.
For control of the beetle you may hand-pick them, but that may prove challenging. Upon sensing movement, the adults drop to the soil and roll on their back, with their underside being black. Some gardeners, including David M. Dion of this office, prefer to use a plant based insecticide called neem oil. The neem tree is found in Southern Asia and India. Used as an ornamental shade tree the seeds are often used in wax, oil and soaps. Neem oil is almost non-toxic for birds, fish, bees and wildlife.