[4] The larva, a caterpillar, is completely covered in long, hairlike setae arranged in spreading tufts.

The hairs cause itchy rashes (contact dermatitis) in many people, particularly those prone to allergies, and may resemble exposure to urushiol.

[4] They are microscopically barbed and may rarely cause serious medical complications if they are transferred from the hands to the eyes,[5] but in over 350 documented cases, most were asymptomatic within 24 hours, and none involved anaphylaxis.

Larvae primarily feed on hickory, pecan, and walnuts, but will also eat ash, elm, oak, willow, and other plants.

[4] They may occasionally cause local defoliation of nut trees, but high densities do not last long enough to cause significant damage.