Black worms on black-eye susans
The best and safest treatment whenever you see caterpillar-type worms devouring your plants is Bt (Bacillus thuringiensis). Bt is a natural product; it's actually a bacteria that is toxic to caterpillars but safe for humans. Use it sparingly, however, because it kills all caterpillars--even those that are destined to become butterflies in your garden. You'll find Bt at your local garden center. If the damage to your black-eyed Susans is extensive, you can prune off the worst of it. These durable perennials will do their best to spring right back up and bloom for you again this summer.
Community Answers 0