Beware! Lurking in many South Florida backyards is a small critter that will offer a terrible surprise if touched. The half to one inch long, stout-bodied brown caterpillar has a conspicuous green back with brown oval outlined in white. It’s unique coloring may entice a closer look by touching or holding it– but don’t! It is a stinging caterpillar known as the Saddleback Caterpillar.
The brown oval marking on the center of its back looks like a saddle on a bright green saddle blanket, hence the silly name. Archaria stimulea (Saddleback Caterpillar) is the larvae growth phase of what will become the slug moth. It is a brown moth that is not so interesting in color and causes no harm. But in the larvae stage as a caterpillar, to protect itself from predators such as other insects, lizards and birds, it’s a hazard to all gardeners.
The Saddleback Caterpillar, though relatively a minor pest to landscape, is a significant medical pest when encountered. The body of A. stimulea has four fleshy horns that contain numerous hollow spines. They are all capable of breaking and embedding when contacting a surface such as theexposed skin of a gardener. The spines contain the venom. If touched, or only lightly brushed against, the venom can cause simple skin irritation to violent reactions in its victims. Adhering to the leaves of its host plant, this tricky caterpillar will arch its back, ensuring all four horns contact whatever is unfortunately nearby.
This caterpillar is found in large numbers in North America, east of the Mississippi River from New York to Florida. Its range is so large since it can live on many host plants that are in our yards, along sidewalks and in our parks. In Florida, they are found on Brazilian pepper, Viburnum, coral vine, Tabebuia, spicebush, pecan, mahogany, dogwood, crape myrtle, and on many species of palms (Sago, coconut, fishtail, Areca, Christmas, queen, pygmy date, to name a few!). Do any of these sound familiar?
While working in your yard around these many plants that could have the Saddleback hiding out, use protective clothing and gloves – DEET is not effective as a preventative. If you do have the unfortunate experience of the venomous sting, it will be felt immediately. The skin will turn red and blisters may form.Pain can last up to five or more hours. To treat, stay calm and remove the caterpillar from the skin if it is still in contact. Using tweezers, remove the largest spines and also use Scotch tape or Duct tape to stick on skin and peel off numerous times to remove as many small spines as possible. Wash skin with soap and water and dry completely. If pain, redness, headache, fever or any other extreme reaction occurs, seek medical attention immediately.
To control this pest, if in small numbers, hand removal of the eggs is suggested. Larger infestations have been successfully treated with a biological treatment: Bacillus thuringiensis or a chemical treatment of diflubenzuron. To treat your yard with these products, check with the local garden center and always apply as the label directions describe.
For such a small, fascinating looking creature, knowledge of its whereabouts in the landscape and great care should be taken around it. For more information on this caterpillar and other pests in south Florida, please visit the University of Florida’s extension website at collier.ifas.ufl.edu/.
For more beach and bird information, please contact Nancy Richie, City of Marco Island, at 239-389-5003 or firstname.lastname@example.org.