Stinging Caterpillars
Many insects display complete metamorphosis- the four life stages of egg, larva, pupa, and adult. A caterpillar is the larva stage of butterflies and moths. Many species have developed various defense mechanisms such as horns, spines, venomous spines, eversible glands, secretions, and body hairs. Some types have good defenses in camouflage to protect themselves from predators, parasites and man. Others display bright colors as a warning for predators to stay back. Still others imitate the colors or actions of poisonous insects while not being poisonous themselves.
Caterpillars can be foliage feeders on shrubs, trees, grass, ornamentals, vegetable plants or weeds or they can bore into plants or trees. Each caterpillar goes through four or six growth stages or molts where they shed their skin to grow and complete development. This focuses on those which have venomous hairs or spines that can cause a burning sensation when touched, producing a red swollen area and for people allergic to insect stings the possibility of anaphylactic shock and death. |
Buck Moth Caterpillar
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Whitemarked Tussock Moth Caterpillar Spiny Oak Caterpillar
General Information:
Stinging caterpillars may live in groups and disperse prior to
pupating or they can be solitary. Host plants are sometimes
specific- for example, the buck moth caterpillar pictured above lives on oak trees. Other
species develop on many types of hosts.
Some species have a single generation each year while
others have multiple generations. Thus, species identification is important for making the best
management decisions.
"Stinging" caterpillars have a series of hollow glass-like
hairs or spines on the body that contain a chemical venom.
When a hair comes in contact with skin, the tip of the hair will break off and the
venom inside enters the open wound
created by the spine. The venom causes burning and
stinging sensation, and the reaction of the human cells to the venom causes the reddening and swelling. Some
people are very sensitive to the venom and may require
medical attention.
 
Io Moth Caterpillar Saddleback Caterpilar
Effects of the rash produced by these caterpillars can be
reduced through the application of over the counter insect
bite and sting products. Home remedies reportedly include
several household materials such as ammonia, Clorox, toothpaste, meat tenderizer in a paste, or
baking soda in a paste. These are throught to neutralize the
acid venom reducing its affects. If they are not available,
one could attempt to remove urticating hairs by pressing a
piece of tape down hard on the affected area and then rip
it off. This catches some or all of the spines and pulls them
out, perhaps closing the wound and preventing more venom
from entering.
Many caterpillars with hairs or spines on their
bodies but not all of them contain venom. Some species
mimic the stinging caterpillars in appearance so they will
be left alone. Identification is important as touching the
wrong caterpillar can be painful.
 
Slug Caterpillar Puss or Flannel Moth Caterpillar
Slug Caterpillar and Puss Caterpillar- two species to avoid touching. The puss caterpillar is sometimes called an "asp".
Locations |
Suggested Thresholds |
Nonchemical Control Options |
Preferred Chemical Treatment |
Other Chemical Treatment Options |
Infested
trees,
shrubs or
plant beds |
One stinging
caterpillar |
Knock off and
mash where
possible |
Spinosad, Bacillus
thuringiensis
var. kurstaki,
(moderate to
slow acting)
|
Other contact insecticides containing
acephate, carbaryl, pyrethroids (permethrin,
bifenthrin, cypermethrin, lambda cyhalothrin)
or others possibly mixed with an adjuvant or
liquid soap can be used populations that need
quick knockdown. |
Anyone making pesticide applications on school property must be
licensed by the Board of Pesticides Control. See “Standards for
Pesticide Applications and Public Notifications in Schools”.
Information on this page is from Texas A&M's IPM plan for Stinging Caterpillars. The original document is available in PDF form below.
Printable Version [PDF]
Photo credits:
Gerald J. Lenhard, Bugwood.org
Jerry Payne, Bugwood.org
Texas A&M
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