Urticating caterpillars are moth
larvae that have hollow spines containing an irritating fluid that
produces stinging and burning in human skin. In Georgia, urticating
caterpillars show up in the late summer and autumn.
Saddleback Caterpillar (Sibine stimulea)
The saddleback is the most commonly encountered
stinging caterpillar in Georgia. The full-grown caterpillar is
about 1 inch long, with pairs of dark brown spiny "horns" on the
front and rear ends. The middle of the body is green with a white
or cream margin, and a large oval dark brown spot in the center,
also with a white margin. The appearance is that of a saddle and
blanket, thus the common name. Small clumps of spines occur in a
row along the lower margin of the green area and at the rear of the
The saddleback is generally a
solitary feeder; however, early stage larvae may be somewhat
gregarious. The caterpillar occurs on a wide variety of trees,
shrubs, and other plants, including corn. They are most common on
oaks, elms, dogwoods, and various fruit trees. People are most
likely to bump into saddleback caterpillars in late summer and
The saddleback's sting produces an
immediate burning sensation, followed by inflammation, swelling,
and a red rash.
Puss Caterpillar (Megalopyge
The puss caterpillar is hairy, over
an inch long, with short toxic spines hidden underneath brown or
gray fur. The hairs at the posterior end form a tail-like tuft,
while the head is tucked under the front. When skin brushes against
the caterpillar, the spines break off, releasing irritating fluid
that produces an immediate stinging sensation.
Puss caterpillars feed on oaks,
pecans, persimmon, fruit trees, roses, and other trees and shrubs.
They typically occur singly, although several may occur on a given
The puss caterpillar causes the
most painful and severe reaction of any urticating species in the
United States. The initial burning sensation is followed by
numbness and swelling, which may extend to the entire extremity in
severe cases. Red blotches may persist for a couple of days,
accompanied by a weeping rash. Associated lymph nodes (axillary, in
the case of injury to hand or arm) may swell and be tender,
persisting for 12 to 24 hours. Systemic reactions may include
nausea and vomiting.
Treatment of Urticating Caterpillar
People gardening, mowing lawns,
picking fruit, or working in other situations where they might
brush against urticating caterpillars should wear long pants,
long-sleeved shirts, and gloves. If stung, the individual should
treat symptomatically. To remove any spines still in the skin, a
piece of adhesive tape can be gently stuck to the site, then pulled
away. Application of cold compresses can lessen pain and swelling.
Over-the-counter pain medications may be indicated, along with
topical hydrocortisone cream. A physician should be contacted if
systemic reactions or other symptoms of concern develop. Symptoms
typically resolve within a couple of days.