Saturday’s big gardening adventure came in the form of a venomous spine lodged in my leg. Ouch!
The culprit — a saddleback caterpillar — was munching on a kale plant. I didn’t even see him. I just stepped away from tending a tomato plant, and backed my leg into the caterpillar’s chosen kale leaf. Fast forward .0042 seconds, and I’m leaping into the air wondering what creature of hell had just attacked me. Based on the suddenness of the pain, I expected my assailant was a yellow jacket, hornet, or baby Velociraptor. I didn’t suspect a caterpillar. Especially not a 1-inch caterpillar.
But that’s exactly what happened. A close inspection of the kale plant I’d backed into revealed a mess of caterpillar damage, a bunch of run-of-the-mill cabbage worms, and a prickly little beast that I vaguely recognized from my trusty Audubon Society insect guide. I knew I’d found my attacker. The little thing was just loaded with short spines. Here’s a photo of him on my poor, half-consumed kale plant. Yes, that’s a head shot:
And, here’s another photo of the beast, taken after I’d very very very carefully removed him from the kale plant:
Prickly! Beware: Every one of those spines is loaded with hemolytic (blood-destroying) and vesicating (blister-creating) venom, and they will readily jab you whether you see the caterpillar or not. Long pants, long sleeves and gloves may offer some protection, but not complete protection — I was jabbed right through the denim of my jeans.
In North America, only the puss caterpillars of the moth family Megalopygidae are more venomous than the saddleback caterpillar.
Here’s how the University of Florida’s entomology guide (the best I found) describes the saddleback’s effects:
The spines of A. stimulea are strong, acutely pointed, and hollow. They embed deeply into tissue and break off, and can interrupt healing as the protoplasm from the venom glands dries into the tissue area. … The venom itself can cause a systemic condition called erucism or acute urticaria, for which severe symptoms may include migraines, gastrointestinal symptoms, asthma complications, anaphylactic shock, rupturing of erythrocytes, and hemorrhaging…
Sounds nice, right?
Reading this, I know I got lucky. No nausea. No migraines. No shock. Not even a rash. Just an immediate burst of super-intense pain that lasted until I removed that venomous spine (only one made it past my jeans) and numbed the area with a cube of ice. Very lucky. I think I escaped the worst of it because I was wearing jeans, which surely offered some protection (though clearly not enough). Also, I found and removed the single spine within a minute of getting jabbed. I was highly motivated — the tiny little spine HURT.
Still, I find it mind-boggling that an inch-long caterpillar can cause that list of symptoms. After a bit of searching around the internets, I found bunches of stories about much worse encounters with these nasty little guys. Some people even wind up in the emergency room. There’s a good collection of folks’ saddleback caterpillar stories here.
After a weekend of compulsive reading, I can offer the following information about these prickly caterpillars:
Full name: Saddleback caterpillar or saddleback caterpillar moth
Scientific name: Acharia stimulea (formerly Sibine stimule)
Range: The eastern half of the United States, from Massachusetts to Wisconsin and south to Florida and east Texas.
Diet: Saddleback caterpillars can feed on a variety of plants. The one that got me was on a kale plant, but reports also indicate they feed on deciduous trees and shrubs, vegetables, flowers, and just about anything.
Life cycle: The timing of this varies by region, of course. Adults appear to emerge at the onset of consistently warm weather (June/July in the far north of their range, February/March in the most southerly part of their range). Females lay clusters of 30-50 eggs, and the larvae hatch in about ten days. The caterpillars hatch and feed in a group until they’ve molted once or twice. Then, they disperse (not sure how far). It appears to take approximately four months for these caterpillars to reach full size, which explains why most interactions between saddleback caterpillars and people appear to happen in the late-summer months; that’s when the caterpillars are larger and more likely to be encountered.
Note: Saddleback caterpillars develop their venomous spines after their first molt, which means that even very small saddleback caterpillars can sting.
How to avoid being stung: I’ll give you the bad news first. You can’t totally eliminate the possibility of a saddleback caterpillar attack. Well, that’s not entirely true. If you live in the eastern half of the United States, you could pack everything up and move west (where these caterpillars are not found). Up to you if you want to take things that far.
Otherwise, it’s just a matter of reducing risk:
- Wear long pants, long sleeves and gloves, especially in the late-summer months (yes, when it’s stinkin’ hot). I’m positive I got off easy because I was wearing jeans rather than shorts.
- Learn to recognize saddleback caterpillars.
- Be cautious when handling or walking past/through vegetation that shows obvious signs of caterpillar damage.
- If you find one, chances are good there will be more nearby. Carefully look over the host plant and neighboring plants. Be careful — you don’t want to feel the caterpillars before you see them. It may be wise to carefully remove the entire host plant (depending upon the plant, of course).
- Relocate or kill any saddleback caterpillars you find. Do whichever you think is best. But, bear in mind that one venomous caterpillar this year could turn into 30-50 venomous caterpillars next year…
However you deal with saddleback caterpillars, keeps this bit of information in mind:
Spines of urticating caterpillars can become airborne and consequently be inhaled or contact sensitive tissues like the eyes and nose. They may also embed in surfaces such as wooden tables and plastics, which become a contact hazard at a later time if the area is not cleaned. Stray spines can also get caught in fabrics, such as carpet, aprons and clothing and come into skin contact that way…
In other words: Be careful.
For even more information about saddleback caterpillars, including some fantastic photographs of the adult moths and young larvae, check out the species summary provided by the University of Florida’s entomology department: Saddleback caterpillars (Acharia stimulea).
Are you familiar with saddleback caterpillars or other unfriendly caterpillars? Any more tips to share that I may have missed? Please click here to add you advice in the comments section below.
Hello,
Thank you for the warning the fine info plus media. I might have one on my chicken coop. Yes, strange perhaps, but I live in MS where everything moving seems to bite.
Good to know that you did not have a serious reaction. But, it did smart!
Courage!
Mary Ann
I just killed about 20-30 caterpillars. I am not sure what kind it was but they were eating my dessert rose plant that was just budding. I had to trim my plant to almost a bonsai. This is the second time between 2-3 years that I have seen this nasty caterpillar. I don’t get it they don’t spread into the other plants? maybe because I killed them before they move on?
if i see any they will be dead dead dead lol so sorry you were stung xx
Wow, how beautiful for o foe! Your photograph of these beautiful creatures is really extraordinary. Thanks for the warning. In New Mexico, I doubt we have them, but because I haven’t seen them doesn’t mean we don’t! Keep up our lovely blog and lovely garden.
Blessed Be, Mitra
Sorry to hear you were stung. I used to live in Maryland and found saddleback caterpillars in the garden almost every year, but I never found more than one a year. I did put them in glass jars, showed to neighbors and warned about the sting. My kids were stung and they did say it hurt but had no other symptoms other than pain and red marks where they were stung.
I don’t remember ever seeing such a creature as that; are they round with stickers are is your photos of them been cropped or altered some way? I have seen many caterpillars but none like those. Hope that is the last sting you ever have by them and this one leaves no lasting results. Happy Fall Gardening to you.
Thanks, Alice. I’m completely fine — very lucky! And, yes, those photos are exactly how they look. Short and prickly, with a pair of “horns” at either end.
Jesus! What a awful little thing! I’m so glad I havent come across one yet! Sorry you got stung. Thanks for the warning & info.
Hey! You didn’t say how to get RID of them. I’ve chopped them off of my ornamental palms, Sprayed a solution of doapy water, even mineral oil. They keep coming back!
I wish I knew how to get rid of them, Char. I’m afraid they’re just a part of life for us gardeners who live within their home range. Hand-picking — carefully! — when you find them is probably the best bet. Or… If they always seem to go for the same plant, you might try dusting them and their plant with diatomaceous earth. It’s totally natural and harmless to us and many insects, but can sometimes work as a control for soft-bodied bugs. Good luck!
Just got “stung” in the finger while removing the small rose bush leaves that 7 or 8 of these little devils were devouring. Flushed them all down the toilet then came to my computer looking for an answer to the throbbing pain in my finger. Guess I was lucky to only have taken a small hit. It REALLY hurts! Going back out with thick gloves later to look for more of the little guys to swirl away.
Hi. I found about 20 of these caterpillars on my rose bush. Not knowing I tried to pick them off to my surprise was the wrong thing to do. The itch and burn came fast. The caterpillars I have are yellow where the green is. Otherwise they look the same. Are these saddleback and is there anything I can use to kill them?????????
I’m pretty sure saddleback caterpillars can range from yellow to green. So, yes, probably the same thing. For control, I honestly just snip them in half with my garden shears. Effective. But, if you want something that will zap multiple caterpillars at the same time, try a spray of soapy water. That’s often enough to get soft-bodied insects, because the soap clogs their breathing pores.
For the first time, I have found them in my yard in New Orleans. They are on my Bird of Paradise and neighboring gardenia. I’ve been stung repeatedly now. Add these guys to our pussmoths, buckmoths, those green caterpillars with spines and it’s getting unsafe to be a gardener.
To ease the pain from the stingers, I found a compress of Ammonia solution left on for 15 minutes breaks down the organic poison from the stingers.
You can kill them safely using bacillus thuringiensis. It gets into their digestive track and replicates until it kills them. It is effective on a lot of cutworms, caterpillars and these slug-like caterpillars (saddlebacks) that turn into moths. I bought powder from WalMart with free shipping from “Seed Ranch”.