Last year was hornworm heaven at our house….:-(
I live in Nor. Cal. at the north end of the valley…..very hot in summer.

I have a large Barberry bush out front and a t. hormworm devoured the entire inside of that plant!
It has thorns, so I was surprised. They also enjoyed my petunia plants along with the tomato plants.

I have had some success with diatomaceous earth sprinkled in the evenings. We don’t get much
rain in the summer and I don’t overhead water, so it stays on for quite some time.
I also hand pick the eggs off, and the few that have been allowed to hatch, I pull off;
when I finally and suddenly SEE IT!!! Such the cameleons!