Tomorrow if its not raining go back out there and look for what I refer to as black poop. The hornworms are usually right above it, the "poop" will be on the leaves or stems. I don't think the rain can wash the worms away, they seem to hang on for dear life. If by some chance you spot one or more with what appears to be white things coming out of its body on the top, leave it, don't kill it, because the white things are actually paralyzing the worm and in fact will kill it without you having to touch it.

The worms come from eggs of a certain moth, sorry I can't remember its name right off hand now. They shouldn't be the cause of your tomatoes not ripening. This has been a very strange year for tomatoes ripening, probably because of the cool spring we had. I"m normally over whelmed with tomatoes by now, but today I picked my first full size one, and even the cherry tomatoes are ripeneing as quickly as normal. Hope this has helped you some.

Alberta

Well, they're big enough that they may well be full grown.

If so, they are now in the soil where they are changing into pupae and, ultimately, adult moths.

Next time you find any that large, the best remedy is immediate action -- stomp on 'em'; drown in soapy water; cut in half; or feed to birds/chickens. Nothing else will work.

Scissors is the answer. Get them immediately. They go into the ground when full of food and come up at night to eat all night. look out they are still there.

I think hornworms become Sphinx moths.

Lorna

Maybe birds ate them.

This may seem strange, but the birds that hang out in my back yard are true buddies of mine. Somehow, they have figured out that when I head for the garden, it's time to gather on the grass. When I find a worm or bug or slug, I toss it onto the lawn and the birds gobble them up. Throughout the day, from the kitchen window, I can see the birds jumping into the raised beds for their morning patrol. They eat there and even get a drink from the drip irrigation. Kinda neat.

I don't believe they go into and out of the ground between feeding. After they reach their last instar and as big as they're going to get as a caterpillar, then they fall to the ground and go into their chrysalis stage to metamorph into a moth.

I agree with Aulani, most likely the birds got them. I have actually witnessed a Cardinal grabbing a hornworm from a tomato vine. There are lots of Cardinals hanging around in our back yard and they patrol our garden every morning, along with several kinds of birds. I love watching them and I'm grateful for their help.

Be careful if you stomp on them... you'll end up with green goo on your shoe and halfway up your leg. I like to scrape a little spot on the ground with the side of my shoe, drop the critter into it, cover him up with the little dirt scraped up, and then stomp on him. Much less messy.

If you find them that have little white things that look like grains of rice along their back, pick them off your tomatoes and put them into another area of your property. The white things will kill the worm and hatch out into beneficial predatory wasps that will then kill more hornworms. It's always nice to have some friendly little helpers in the garden.

I had the same type of thing happen, but then they came back. Those little buggers have almost perfect camouflage and are sneaky little buggers. I found what mine have been doing is eating my pepper plants at night and during the day they are no where to be found. I found them though, they moved into my tomato plants to hide. I have determinant varieties that they have not eaten one leaf off of, guess they don't like the taste, but they love to hide in there because of the dense leaves. Look around, they may be hiding in another plant nearby, or they may have started to pupae. If that is the case, use small had rake and move the soil around the base of the plant. They will be in the the top 2 inches of soil. The chrysalis has a distinctive loop/hoop on the end. If you find them, take them off somewhere else. (I try not to kill them at this stage if I find them.) The sphinx moth is a great pollinator of tube-like flowers, but the larvae are a royal pain. I have found that a mixture of garlic spray, cayenne pepper, old coffee, and a little neem oil at least keeps them at bay, along with other little pests. The garlic helps to hold off fungus, the cayenne controls aphids, the coffee helps with just about everything(caffeine is a neurotoxin, thats why is makes you jittery and to insects it can be lethal if they injects too much.) and the neem oil helps control other insects and fungus as well as makes things stick to the plant. Repeat every 7-14 days or it the leaves get wet. It took me weeks to finally get them under control, so just keep at it and be persistent. Also, the parasitic wasps that come from the white sacs found on them are a great thing to have. If you find them, put the caterpillar and all in a jar with a few leaves from tomatoes or peppers. Wait until the caterpillar dies and then put him back in the garden. The wasps will hatch and attack all the others, plus the wasps should overwinter near there and will be back in the spring to help out.

I want to thank everyone for all their suggestions and help. Just to follow up, yes they did come back! Although I haven't found as many as I saw before the rain I did find quite a few and I am checking the plants everyday for more. I will check in the soil for the chrysalis today. Wish me luck!
-Katie