Puss Caterpillars(Megalopyge opercularis) – Beware!
By George Giltner, Adv. Master Gardener
“Oh! What a cute little furry bug”, then “Ouch, the SOB stung me worse that a bald faced hornet!” Welcome to the poison spines of the Puss Caterpillar, Italian asp, Spanish perrito, wooly slug, or the numerous unprintable common names given to this caterpillar. Note: all larval developmental stages have hollow spines with base venom glands, but the above last instar delivers the worst stings.
For some people this furry southern flannel moth larvae’s sting is serious enough for a medical visit. Beside the painful sting location, additional symptoms like headache, fever, nausea, vomiting, tachycardia, low blood pressure, and seizures may occur. Rarely, convulsions, chest pain, numbness, muscle spasms, and abdominal pain are the results of the protein toxin from the multiple spines along the dorsal side of this caterpillar.
If you are a victim, remedies first include removal of the broken spines. No! Do not try to scrape the spines out, as some will inevitably be driven deeper in the skin. Lightly apply Scotch tape or better, clear Gorilla tape to remove the broken spine tips from the skin. Then recommendations include ice packs, oral antihistamines, hydrocortisone creams or baking soda to the sting site. Medical treatment may include systemic corticosteroids and intravenous calcium gluconate.
Outbreaks have historically occurred. Even schools have been temporarily closed as cycles peaked. However, most years, varieties of natural predators keep populations of the puss caterpillar in check. Among these are at least two types of ichneumonid wasps, and four species of tachinid flies. Applications of “Bt” to the affected plant’s leaves are effective when populations become noticeable.
As one of the most venomous caterpillars of the United States, and as an endemic southern leaf-feeder of oaks, elms, citrus, and roses – encounters with children are common, especially in the Fall. They are not only found on the leaves of trees and bushes. They may be spotted crawling on objects in the vicinity including toys, walls, buckets, etc. Parents should ensure that children are educated about poisonous caterpillars along with spiders, wasps, ants, centipedes, and other stinging critters. Puss Caterpillars resemble a “Persian cat” bug to young children. However after they are stung, parents have to endure at least a week of painful cries from their children.