Why they are Beneficial
The wasp stings the caterpillar which paralyses it temporarily, thus enabling the wasp to lay an egg on it. When the larva hatches it will hang onto the caterpillar waiting for the caterpillar to enter the soil where it would normally pupate. Once the caterpillar has made its pupation cocoon, the wasp larva will begin to feed on the caterpillar then it will use the prepared cocoon to pupate in.
They feed primarily on helicoverpa, armyworm, heliothos and moth caterpillars. They attack caterpillars from their third instar, but more often the larger fifth or sixth instar.
