Whiteflies and worm castings

[GrannyG]

I worked at a friends hydroponic tomato greenhouses for a summer, they also grew beautiful red bell peppers and got an invasion of white flies. We were only allowed to use a spray mixture of denatured alcohol, added to this was a few drops of Palmolive dish soap and it was added to a gallon or so of water. This solution was sprayed on the plants and killed the white flies. We also used it on the tomato plants for various problems. The local University gave him the advice to use this solution.