My mother in law always did this, I though it was the chemicals in the peel that made it work so well. Just flatten a banana peel and bury it under one inch of soil at the base of a rosebush. The peel’s potassium feeds the plant and helps it resist disease...works for tomato plants too.
Non toxic tomato worm control . I don't remember where I learned this, but I've been using this method for 30 yrs and it really works. Get yourself an old jar & poke holes in the lid. Fill the jar with plain white flour and sprinkle it liberally over your tomatoes. I've never had an issue with horn worms or other pests with this. I also use it on cabbage & broccoli with good luck.