A few weeks ago I was in the “Three Sisters Garden” picking the delicious rattlesnake beans that were climbing up the corn plants when all of a sudden I felt a very painful stinging sensation on my forearm. I couldn’t figure out what had happened. I thought at first that I had gotten scratched by the edge of a corn leaf but the stinging was very intense and I knew something else had gotten me. I looked around on the corn plant where I had been picking and saw a cluster of crazy colored caterpillars on the underside of a corn leaf. As soon as I saw the spiky hairs on those caterpillars, I knew they were the culprits. Boy, did it sting! I snapped this picture of them with my phone so I would be able to identify them later. Sorry for the poor photo. This past Saturday Eric bumped into another one as he was picking more corn – he promptly put gloves on! I was glad I was able to get some better pics!
It turns out that these very colorful caterpillars were saddleback caterpillars, the larval stage of a moth (Acharia stimulea) which is commonly found in the eastern half of the United States.
The saddleback caterpillar is aptly named for the large brown spot that resembles a saddle in the middle of its bright green abdomen. At both the front and back of the abdomen are a pair of prominent fleshy “horns” that are covered with sharp spines called urticating bristles. These bristles are hollow and contain a toxin that causes a painful sting when you inadvertently rub up against the caterpillar. They are very similar to the hairs that are found on stinging nettles and cause the same type of irritating sting but in my experience the sting of this caterpillar is many times worse!
The bright coloration of these caterpillars is a warning sign to stay away! Too bad I didn’t see them before I bumped into them!
My arm turned quite red and swelled up in the area of the stings and the stinging went on for hours. It was quite impressive! Now almost 2 weeks later, it still itches a bit and I can still see the red bumps where the spines must have imbedded.
As I researched this particular “stinging” caterpillar, I discovered that, because of its rather large urticating spines and relatively potent venom, the saddleback caterpillar is considered one of the most dangerous of the stinging caterpillars; perhaps second only to the puss caterpillar. Yikes – I guess I was lucky that I just got painful rash!
It turns out that though these caterpillars are found most commonly on various trees and shrubs, they also enjoy eating the leaves of corn! I could see the damage their feeding had caused on the corn foliage. There were tan streaks on the leaves where the caterpillars had scraped the green tissue between the leaf veins.
This week we had an inquiry about another colorful caterpillar, the milkweed tussock moth caterpillar. These hairy orange and black caterpillars are often found at this time of the year on their favorite host plants, the milkweed. I don’t think these caterpillars sting but I for one am not going to risk picking one up to find out!
Milkweeds are also the host plant for the caterpillars of the beautiful monarch butterflies. I have just recently started seeing monarchs flitting around the Buddleia and Helianthus flowers at the nursery. The black swallowtails and yellow tiger swallowtails have been around for a while but I’m always happy to see the monarchs which usually arrive a bit later in the season. These large butterflies are so majestic and fun to watch!
Meanwhile, beware of the spiny caterpillars!