The theory behind using worm castings is that chitinase in the worm castings is absorbed into the plant and is lethal to insects that visit the plant. The worm castings on the ground do not repel whiteflies, so sprinkle them about the dripline of the plant (not around the trunk) and water them in.

Thank you, lgteacher and chloebud!!! Very very helpful.

After you make your morning coffee, run another batch of water thru those same old grounds. Spray that diluted coffee on your white fly infested plants. See how that works.

Bob Tanem , the radio gardener in SF (on KSFO) says it works for him. Nothing to lose, everything to gain?

-Babka

You can do the same thing with plain ol' water.

I can knock off aphids with plain water, and they don't come back, but plain water just sent the whiteflies flying in a cloud and they came right back. Guess it depends on how bad the infestation is.

-Babka

Thank you, Babka and lgteacher!

I appreciate the suggestions, however the situation is too out of hand to deal with via spraying water. It is a bunch of tall trees, it would take hours, and then still probably wouldn't work.

I bought the jumbo bag of castings. ; ) I am shemailing the local county garden folk to see what they say. I already put some down and watered it in as best I could. I couldn't get up all the leaves. I am trying to find out how much and how often. It doesn't sound like you could hurt a plant with castings, but, I'd hate to find out too late.

It is my impression that mosts pests don't actually kill the plants ... right???? Please say yes!