The very hungry reclassified caterpillar

Not, in fact, a tomato hornworm.

tomato hornworm caterpillars

Last week I posted about the voracious caterpillars that decimated one of my tomato plants. I theorized, based on as close an identification as I could make, that it was a tomato hornworm, Manduca quinquemaculata.

Made sense. Fat, green guys with white stripes and brown spots? Check. Horns on their rear ends? Check. Munching on tomatoes? Check. My guys’ stripes weren’t as fat as the ones in the photo from the University of Minnesota Extension publication, but perhaps I had juveniles? Maybe after eating my entire plant, the stripes would grow as bloated as the rest of their bodies.

Not so fast. Enter iNaturalist, a fabulous nature-identification app that I’m in love with. Created as a joint project between the California Academy of Sciences and the National Geographic Society, it allows citizens to upload their observations and get critter identifications from other members. The data are shared with databases like the Global Biodiversity Information Facility, so you can feel good about contributing to biodiversity science.

Everyone on the app piled on to correct me. I don’t have tomato hornworms, although my mistake is a common one. I have tobacco hornworms, Manduca sexta. This link shows the differences very clearly. Tomato hornworms have V-shaped stripes and bluish- or black horns on their rear ends. Tobacco hornworms have white diagonal stripes bordered in black, and have red horns on their butts.

White stripes, red horns. Clearly, tobacco hornworms.

Treatment is the same: pick ’em off and feed them to hungry birds. I’m happy to report the sad, naked tomato stalk grew a few new leaves this week, so maybe it will pull through.

Here at MHM, we believe in science, so I wanted to correct the record. 🙂


The very hungry caterpillar

Yesterday’s healthy tomato plant reduced today to a stick? Tomato hornworms may be to blame.

What’s new in your garden? In mine, it’s tomato hornworms.

My vegetable garden is in a location where I walk by it virtually every day. One day, my plants were tall and lush. The next day, one looked like this.

tomato plant foliage stripped off

Holy cow. It couldn’t have been deer or groundhogs; the garden is fenced off in a way that prevents either of those from invading. A closer look (much closer, because the little rotters are exceptionally well adapted to their dinner of choice) revealed them to be tomato hornworms, Manduca quinquemaculata.

These suckers were, as you can see, the size of an adult thumb after having munched a five-foot-tall tomato plant to the stalk.

tomato hornworm caterpillar manduca quinquemaculata

How to treat tomato hornworms

Being an eco-friendly pest management type, I grabbed a pair of scissors from the kitchen (I will touch a lot of things in the garden, but not these guys) and snipped off the part of the stem where they sat munching away. With a collection bucket in hand, I dropped the stalk remnant and fat caterpillars into it, then collected another three (thankfully, much smaller) ones from adjacent plants. I dropped them in soapy water and disposed of them in the garbage. Alternative control methods include Bt (Bacillus thuringiensis) and insecticidal soap, but using scissors means you don’t have to go out to the store.

Monitor plants several times a week to stop these guys before they decimate your entire tomato planting. (Decimaters…?)