I read that you can see tomato hornworms with a UV (ultraviolet) light. Two nights ago we went out to see if we could spot them. I had gotten a UV flashlight last year but didn’t receive it till after the first freeze so there wasn’t much to see. But not that night! In the daylight I could only see the chewed up leaves on 2 plants but could not find the hornworms. But at night they are easy to spot with the UV light. We found many small ones as well as big ones that we would have missed if not for the UV light.
Also we noticed that there seem to be either fluorescent bite marks or trails where they had been so if we saw these we would see if any were hiding. We probably got 30 tomato hornworms in all. What a great way to find them.