Where do you live? Those dropping look odd, my guess is a chipmunk or squirrel - but droppings look different. I am not sure on this, odd

Most animal do not poop where they eat, let alone on what they eat.

We are outside of Toronto, zone 5. Chipmunks and squirrels are often in our yard...

Thanks Robert. googling caterpillar poop brought up pictures just like what we have! It did not specify what kind though... and if I can do something about it...however the article did mention caterpillars feeding on corn. We do have corn within 15 feet of these tomatoes, and some of the ears are quite deformed...so maybe caterpillars, although I never saw them there.

Although big, hornworms, being green, have a knack of blending in. The sparse top of the plants you mention points to them.

tj

We have what are called climbing cutworms here. They hang out high up in my tomato plants and do damage like that.

If you can find and dispatch the culprit(s), those tomatoes might scar over and continue to grow.

Must be one of these guys, and it must be huge by now

Yep,agree, and finding him is going to be our next job

A big tomato hornworm. They are tricky to find. Usually, they eat the leaves. Look for any poop with a green tinge to it as that would be the most recent. The caterpillar won't be far away...... Good luck!

Generally here Hornworms will chew up the foliage near the top of the tomato plants leaving bare stems in their wake. Your "worms" may be the same type that attack corn and mainly chew on the tomatoes. If you don't find any present on the plants then a predatory wasp or hornet may have found them first and carried it away for dinner.

That would have to be a whopping great big predatory wasp vgkg!!!! {LOL}

I have had them on my tomatoes but never noticed poop. Seems likely I would have never thought if that great job guys!!!!!!!!!!!!!!

Ha, yeah for sure a Hornworm is on the heavy side Labradors, but the smaller brown worms are easy prey for my local paper wasps. Hornworms are left on the plant to feed the Braconid wasp eggs laid upon them...

It's a cruel world, nyuk.

No, so far these beast are still around, I see more damage to stems as well as tomatoes and poop in various places, but no caterpillars. Have tomatoes growing in two areas ca 100 ft apart, first I saw damage where most tomatoes are as well as some corn, than in the other area where I planted several "afterthoughts" ( no more room, but I really wanted to try out these varieties too).

How do I find them ?

When do they feed ? time of day ? Night ?

I'm pretty sure they feed contantly ... you just have to look really hard; I have no better advice for finding them, sorry! I usually have the can't find it, can't find it, can't find it ... oh! wow, how did I miss that monster? And then don't take your eye off it until it's no longer a threat.

Go out with a black light flashlight as it's getting dark. They will have a glow.

Climbing cutworms feed at night. They hide during the day, sometimes curled up under leaf litter/mulch/loose soil near the base of the plants. As I said, the ones I have will hide up high in the plant as well - in between and under leaves where they overlap.

And paper wasps will easily dispatch a caterpillar many times their size, then masticate it and carry the pulp back to their nest.

They always seem to be on the bottom side of stem, once you know where to look, pretty easy to find

FWIW, hornworms aren't the only green caterpillars that eat tomatoes. There are some that will blend in and look like a rib on a leaf. I scout my plants carefully and often for damage and frass (droppings), checking the undersides of leaves and squishing any I find.

Thank you all, you folks are great! With your help we caught two fat tomato hornworms so far, in the area where we have only three tomato plants.

We could not find any hornworms in the main garden where there are 12 tomato plants, although there is plenty damage. I did see a hornworm moth sitting on a cosmos flower nearby, but we were not able to catch it .

I noticed that there is no damage to tomatoes where there is a row of tomatoes in front of marigolds and behind basil... would basil be the magic ingredient to keep the worms away ? There IS damage to three plants along the other side of the garden where the tomatoes are planted in front of marigolds and alyssum, with peppers in front of the tomatoes. The alyssum has spread a bit around some tomato plants, making it difficult to search for hornworms.

Cindy, what is a black light flashlight ?

It's the size of a flashlight, but it's a blacklight (gives off ultraviolet instead of visible light).

Thanks. Seems there are many varieties of different strength and prices of blacklights. Some complaints by several people saying theirs did not work. Whoever used one successfully and found the worms, could you please share the specs so I buy the right thing??