The numerous variations in the Corn Earworm Moth are equally manifested in its maize-eating caterpillar.
Corn Earworm Moths come in such different forms, when collected and placed next to each other, they look like moths from a different genus. Some are a tawny, golden brown, while others have deep green hues. Still others are a mix of both pale brown and pale green. All adults have green eyes, which is not that common among moths, making it a helpful feature for narrowing down an identity. Most adults also have a round spot with a dark dot in the center of each forewing. A brown or dark scalloped line near the bottom of the wings has white or white-and-black dots at the pointed tips. Dark wavy lines in the upper area of the forewings may be visible, or may be faint depending on the individual.
The corn-loving caterpillar comes in a variety of colors, too. They may by brown, orange, or green, with pink, yellow, or black markings on them. The fleshy body is covered in tiny spines, giving its surface a textured, almost rough feeling. Because their preferred host plant is a critically important staple crop, this species has been, and continues to be, studied. If the larvae aren't preventing pollination by chewing at corn silk, they are found eating ripe kernels inside the corn ear. They also eat other popular vegetable crops like tomatoes and lettuces, eating the fruit, and sometimes burrowing into lettuce heads. Adults migrate north and can produce multiple broods in a year. Larvae can pupate through cold winters in the northern U.S., but populations in southern Canada are replaced by migrants each year. Some areas can have a mixed population of caterpillars that overwintered combined with caterpillars from newly arrived adults. These areas usually experience more crop damage because of the volume of insects.
Controlling the population size of the Corn Earworm Moth is important for saving harvests. Trapping adults with lures helps reduce reproduction. Artificial selection has helped grow corn lines that have tighter husks, making it harder for caterpillar to get into the ear. Genetic engineering has introduced a gene that produces an insect toxin, made by a bacterium called Bacillus thuringiensis, inside the corn which kills feeding larvae, reducing their numbers and the amount of damage they do. Concerns about earworm resistance to the toxin are inspiring new techniques to manage this insect's population. A management strategy that uses all of these methods together has offered the best results thus far.
Look for adults taking nectar from flowers, or flying in and around cornfields.
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.
Butterfly and Moth Anatomy
Antennae: Butterflies and Moths have a pair of antennae on the head used as sensors.
Head: The head is home to the insect's eyes, antennae, and proboscis.
Thorax: Home to the three pairs of legs as well as vital internal organs.
Abdomen: Contains vital internal organs such as the heart(s) and reproduction facilities.
Forewing: The upper, forward wing pair used for flying.
Hindwing: The lower, rearward wing pair used for flying.
NOTE: Butterflies and Moths are part of the Lepidopteran order as they share many similarities.