I have never heard of hornworms being a problem on strawberries or corn, but if you see them just pick them off and fling them as far as you can away from the garden. Something will have a nice lunch.
Alternatively, if you must use a chemical on hornworms, bacillus thuringiensis (BT) powder is effective. It causes suffering, but in the case of hornworms I actually don’t mind that! s
Plant marigolds as a deterrent around or between your plants. Marigolds stink to a lot of different bugs and they avoid them.