August 1996
SIZE: 2 ½ to 3 inches (75mm)
COLOR: Green with pink and white stripes along the sides.
DESCRIPTION: A mature io moth caterpillar may be up to 2 ½ inches long. They are a beautiful pale green color with white and red stripes on the sides. Short spines radiate from numerous tubercles on the back. These larvae feed on alder, ash, birch, cherry, elm, locust, oak, sassafras, and other deciduous trees and herbaceous plants. They are not uncommon in corn fields.
HABITAT: Open woods and meadows, occasionally cornfields.
TYPE OF DAMAGE: The poisonous hairs or spins are hollow and connected to underlying poison glands. Contact with them causes a burning sensation and inflammation that can be as painful as a bee sting. The irritation can last for a day or two and may be accompanied by nausea during the first few hours. Usually the site of contact reddens and swells much like a bee sting.
CONTROL: A person "stung" by a poisonous caterpillar should immediately wash the affected area to remove any insect hairs and poison that remain. An ice pack will help reduce swelling, and creams and lotions containing steroids will lessen the discomfort and promote healing. Persons known to be sensitive to insect stings should consult a physician. Stinging caterpillars rarely occur in sufficient numbers to be considered plant pests, but people who work with ornamental plants should learn to recognize them and avoid touching them.