Q: I discovered a worm on my tomato plants so I used an insecticide recipe I found online, a mixture of water, rubbing alcohol and dishwashing soap. The next day, my tomatoes had black streaks in the stalks, the leaves were turning black, and the leaves of the other plants were dead-looking.

A: Yow, you made a big mistake! Dish detergent and alcohol dissolve the natural waxes that protect plant leaves from drying out. Your leaves were “scalded” and now you see the results. Retail insecticidal soap would have been a better choice. Wash the plants thoroughly and wait to see what happens. Some leaves may survive and help your garden endure your chemical attack.