This Distance Diagnosis Web Site allows UWEX Agriculture Agents to post questions to Extension Specialists. This looks like corn earworm. Recommendations and positive ID requested. Corn was planted late and is just starting to dent.
Photos reflect stage of insect development.
These are Corn Earworm larvae and the damage shown on the ear tip is typical of feeding injury. Larvae have a wide range of base colors that include green, yellow, brown and rust. Some are nearly black. Adults do not overwinter in Wisconsin. Adults will stay around until frost.