The Coalition to Save the Elms recommends that property owners use only products containing Bacillus thuringiensis,a biological control product aimed specifically at caterpillar-type insects. The biological insecticide is sprayed on the leaves which are then ingested by the cankerworm larvae. Ensure that a biological, not a chemical control will be applied. Insecticide such as malathion kill other beneficial insects and are harmful to the environment. When to band your trees To avoid cankerworm problems in the spring, band your trees in the fall by September 15th or before the first frost.
Bands remain on the tree over winter.
In late winter or by March 15th, check your bands to see if more tanglefoot should be applied to protect the tree against the spring cankerworm. If the band is coated with moths and other debris, the spring cankerworm moth can crawl over the band. A fresh application of tanglefoot may be required. When to take the bands off Bands should be taken off by May 15th . A good rule of thumb is to band the trees on the September long weekend and take them off on the May long weekend.