Stinging Caterpillars – By Mark Govan, Host “Florida Gardening”

During the past week I had a call from a client that wanted my company to come out and identify a problem he was having on his hibiscus. These types of calls are normal for us so we dispatched a technician to help identify the problem. The hibiscus plant was indeed stressed because the plant was being devoured by caterpillars. Normally, controlling a caterpillar problem is simple problem to resolve but this particular caterpillar just happened to be one of the poisonous caterpillars we have in Florida. This article will detail several of the main poisonous caterpillars we must all be on the look out for, what to do if we are stung by these caterpillars, and how to control these pests in our landscape.

            This particular caterpillar infestation was caused by the IO Caterpillar. IO caterpillars (Select photos from IFAS) are about two inches long and are pale green in color with spines crisscrossing the entire length of the body. One of the main identification marks is the red stripe which runs across its body lengthwise with a smaller white stripe directly below this red band. These bands are a direct contrast to the pale green color the rest of its body exhibits. When you find this caterpillar in the landscape, your eyes will be drawn to these contrasting colors and you may even want to touch the caterpillar. This is where many people run into problems.
              Although I mentioned these are stinging caterpillars, I am referring to the pain associated with coming in contact with the poison spines along the body of the caterpillar. When an intruder brushes against these spines and breaks them, the poison is released. This defensive action is automatic and painful. You may never see the caterpillar but you will remember the pain. If you have ever tugged on a stinging nettle weed in the yard, and you remember the pain associated with that, then you never forget the sensation of being stung by one of these caterpillars. In fact, for some people the sting of one of these caterpillars can be far worse.  

            I have had some people refer to the sensation as a bee or wasp sting but when they look at their hand there is no sign of what stung them. This is because the caterpillar is rarely removed from the plant when they sting you. What you have done is broken the spines on their body releasing the poison which has gotten on your hand or other exposed area. If you know that you have been stung by a caterpillar you will need to find some duct tape quickly and pull off a piece placing it directly over your injury. Press the tape lightly over the affected area as not to push the broken spines deeper into your skin. Now remove the tape. Strong tape will help dislodge the spines from the skin. You may need to repeat this process repeatedly to remove all the spines.

            Certain people may have severe reactions to this poison, especially those people that have had problems in the past with hey fever, allergies, and asthma. If a severe reaction persists or you have had any of the above symptoms in the past, you should call a physician. Ice packs may help to reduce the swelling and applications of a paste made from baking soda and water have also been used. Several of my friends have even poured a cold beer over the wounded area and have had some relief. The best way to avoid these caterpillars is to be vigilant and scout your plants for an infestation. Try to remember the descriptions of these caterpillars and spray your plants with Dipel or Thuricide to kill caterpillars once you have found them.

            The next caterpillar you need to be aware of is the Puss Caterpillar. Puss caterpillars are hard to find because of their brown color. These caterpillars seem to blend in with their surrounding environment and are difficult to spot unless they are actively feeding or moving. There is no one plant in particular this caterpillar likes to feed upon but normally they can be found feeding on plants such as oaks and citrus. One key identifying characteristic you may find easy to remember is that this caterpillar resembles a one inch arch, meaning the front and back end of the body are lower than the middle. The caterpillar also has a Mohawk or ridge of soft hairs which stick up from the midsection. Do not let these hairs fool you. Under these soft hairs are stiff spines attached to poison glands. When broken off, these stiff spines embed themselves in the skin causing severe pain. Normally, predators keep these caterpillars from becoming a problem but if you need to kill them use either Dipel or Thuricide.

            Saddleback caterpillars are another one of our more colorful poisonous caterpillars. I have seen saddleback caterpillars on citrus trees in great numbers feeding on the foliage. This one inch-long caterpillar is brown in color with what resembles a green blanket with white margins covering the center of the caterpillar’s body. If you were looking directly down on the caterpillar you would see a brown circle in the center of the caterpillar with a white ring around it surrounded by a lime green blanket which covers all but its head and abdomen. This area closely resembles what the caterpillar is named for, the saddleback. Spines on the front, sides, and rear of the caterpillar hold the poison which when broken, affect the skin.

            Although there are several additional stinging caterpillars which can be found in Florida, these are by far the most common ones I personally have run across in the garden. For a complete list of additional poisonous caterpillars which are found in Central Florida please visit the University of Florida IFAS or the County Extension Office in your area. Because summertime is the time of year many of these caterpillars start to multiply, you should be able to recognize them far easier from their photographs here. If you locate a caterpillar and you are not sure about whether or not the caterpillar you have is poisonous or not, you should carefully collect a specimen and have it identified by a professional. If you wish to control any of these caterpillars on your property you can spray your plants with BT, Thuricide, or Dipel! I hope you have enjoyed this week’s selection and remember, withoutplants we would not be here!

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