Q: The leaves on my basil plant have been eaten by something. There are holes in the middle of most leaves.
A: The holes could be caused by slugs, snails or caterpillars. To differentiate, put a saucer-ful of beer near the plant base one evening and check on it the next morning. If slugs or snails are drowned in the beer, repeat the process for several nights until you capture no more. If slugs or snails are not present, caterpillars must be the culprit. Spray the leaves with organic Bacillus thuringiensis insecticide.