The species Helicoverpa zea is commonly known as the Corn earworm and is commonly mistaken for the corn borer, but can be distinguished through the lateral stripes found on its body and its larger size. The earworm causes most of its damage on the top third of the ear tip in the larval stage, therefore, scouting for the small larvae is critical to prevent damage and yield losses.
The species Helicoverpa zea vary in colour from light green to yellow. The larvae, when full grown, reach a size of 4 cm long and have prominent stripes running the length of their bodies. The adult corn earworm is tan in colour with wings that have distinct central brown markings on the fore part.
Optimal conditions for infestation
Areas where adequate crop rotation is not performed and zones where adequate weed control and management is not effective can easily promote higher infestations of the Corn earworm.
Locate 5 sets of 10 plants per field and open the ear to inspect for feeding damage or larval presence, including the presence of ear moulds carried in by the pest, as the Corn earworm feeds and produces damaged plant tissues and excretes on them.