The creamy larvae have a distinctive double row of brown or black spots down their backs, located at the base of long bristles. The Lucerne moth larva is somewhat larger than the other sod webworm larvae. During the day larvae reside in silk-lined burrows, writhing when disturbed. At night they emerge to feed. Later instars notch or cut off leaf blades and pull them into the burrow.
Significant damage can occur on drought-affected bluegrass and on bentgrass green and tee areas.
Lucerne moths are primarily a problem where clover and dichondra are mixed with turfgrass. The extensive soil or thatch contact of sod webworms makes Steinernema carpocapsae nematodes a valuable control measure. Bacillus thuringiensis subsp. Control of clover and dichondra may help minimize damage. If Bt is used, apply it when there are predominantly early instar larvae.