I am currently in decision mode on treating for rugose spiraling whitefly. I have a dozen or so trees and shrubs on the current list of hosts and have only seen a couple of spirals so far.

My question is regarding using the drench. How far does the drench permeate in the area surrounding the tree/shrub? For example, I treat a copperleaf shrub that is in the same bed as milkweed. How far from the shrub is a safe distance for the milkweed, or is there such a thing as a safe distance from a soil drench?

Thanks,
Terri