A few days ago, I tried a recommended worm & caterpillar biological insecticide on all my plants.. We have been enduring an onslaught of baby munching caterpillars and it was time to take action. It is called Monterey B.t. and cost a small fortune (at my local garden nursery - not Lowe's or Home Depot and to my utter amazement it stopped the eating party in its tracks.. No claims are made to actually kill the critters.. Just to interrupt the feeding after a single bite.. I sprayed on all leaf surfaces, including the flowers, and everything is none the worse for the experience.. I have found many little corpses hanging on by a thread so obviously this product is a killer too.. Hope you never need it, but if you do, this product is a winner.