15
Jul
2013
Stinging Caterpillars

stinging caterpillars

It’s that time of year again.  A couple of weekends ago (6/29/13) while I was weeding a flower bed, I inadvertently grabbed a stinging caterpillar (buck moth) along with the wild strawberry stringers I was removing.  Even though I was wearing cotton garden work gloves, I got stung.  Ouch!

The key here is to be able to recognize the different kinds of stinging caterpillars that may be encountered in our area and then, avoid contacting them.  If you’re not sure of the identification, avoid touching any hairy caterpillar (dead or alive) with bare hands.  So here, we will emphasize identification.

IDENTIFICATION.

The more commonly encountered stinging caterpillars that you should be aware of are:

  1. Buck moth caterpillar.
    • The mature larvae are about 1 1/4″ (33 mm) long.  They are brown to purplish black with longitudinal yellowish to dark orangish lines or rows of such spots, and numerous branched reddish spines covering the body. 
    • The short stinging hairs are located on numerous short spines.
    • The larvae tend to stay together and move in long lines.  They feed primarily on oak.
    • They burrow into the ground to overwinter and pupate there without a cocoon.
  2. .   Io moth caterpillar.     
        
    • The mature larvae are about 2 1/2″ (63 mm) long.  Its color is bright yellowish green with a red longitudinal stripe bordered by a white line below on each side. 
    • It is covered with greenish tufts of short stinging spines.
    • The larvae tend to stay together and move in long lines.  They feed on birch, clover, corn, elm, maple, oak, pawpaw, rose, willow, and many other plants.
    • The larvae spin a thin, papery cocoon on the ground in which to overwinter in our area.
  3. Monkey slug caterpillar. (also called the hag moth caterpillar)      
        
    • The mature larvae are about 3/4″ (16mm) long.  The body is furlike, covered with numerous short hairs.  They are brown and have 9 pairs of sideward projecting easily detached fleshy processes.
    •  The 9 pairs of sideward projecting processes all bear stinging hairs.
    • They feed on apple, ash, birch, dogwood, hickory, oak, persimmon, willow, and other woody plants.
    • The larvae overwinter in cocoons in which they have incorporated the stinging hairs.
  4. Puss caterpillar.  (adult is called the southern flannel moth)      
    • The mature larvae are about 1″ (22 mm) long.  The body is furlike, covered with long soft yellow to brown to gray hairs. 
    • The stinging hairs are intermixed and hidden among the furlike hairs.
    • They feed on Apple, hackberry, oak, persimmon, rose, and other trees and shrubs.
    • They overwinter in a cocoon.
  5. Saddleback caterpillar.      
    •     The mature larva is about 1″ (25 mm) long.  It is brown on the front and rear ends, on its top side in the middle it has a distinctive brown shield (the saddle) surrounded by a white ring that sits on a large green saddle-blanket like marking. 
    • The spines are located on short body projections/pegs and on 2 long pegs/horns on the front and rear ends.
    • They feed on apple, aster, corn, dogwood, elm grape, linden, maple, oak, Prunus spp., sunflower, viburnum, and many other plants.
    • There is one generation per year in our area.
  6. White flannel moth caterpillar.      
    • The mature larvae are about 1″ (25 mm) long.  The body is furlike, densely covered with long soft creamy white hairs that turn dark with age. 
    • The stinging hairs are intermixed in the furlike hairs.
    • These feed on deciduous shrubs but prefer hackberry and redbud.
    • There is one generation per year in our area.

IF YOU ARE NOT SURE OF YOUR IDENTIFICATION.

For your safety, the Rule-of-Thumb is: If you’re not sure of the identification, just avoid
touching any hairy caterpillar (dead or alive) with bare hands.   Take a picture or two.  Then you
can probably make an identification and enjoy your caterpillar find that way.

CONTROL IF FOUND INDOORS.

If these caterpillars are found indoors, it is usually a case where potted plants or cut flowers have been recently brought inside.

  • If the caterpillar is still on the plant or flowers, it should be captured in a jar or other suitable container by putting the container under the caterpillar and dislodging it with tweezers or a spoon, and then releasing it outdoors. 
  • If the caterpillar is off the plant/flowers and on the table or floor, then put the open end of the container over it, slide a 3x5 card slowly under the container’s opening, invert the container and gently brush the caterpillar off into the container, and then release it outdoors.

SUGGESTION: if you have children, print a copy of this and post it on the fridge or wherever your children can see it.

-Eric H. Smith, PhD, BCE
Dodson Bros.
7/2013