Another side-by-side comparison of H. virescens (Left) and H. zea (Right). The dark spot on each H. zea forewing is a field identification character.
The "Heliothis" trap (right) and the "Texas Cone Trap" (left) are two common sampling tools used for both of these species.
The larvae of these two species can be distinguished but it requires one to remove the mandibles and examine them under a dissecting microscope. Budworm larvae have a mandibular process, a retinaculum, that is lacking in corn earworm larvae.
Mandibles from a corn earworm larva (left) and a budworm larva (right).
Same mandibles at higher magnification. Note the retinaculum in the center of the budworm larva's mandible on the right. This process is lacking on the earworm larva's mandible on the left. These differences can be distinguished with a hand lens once the larvae have reached a half inch or so.