Question
I have a scale problem on my arbavitaes. I have been told that I could not spray them until late winter or early spring. I am concerened about allowing this problem to continue to grow until that time.

I understand the idea of not wnating to "smoother" flowering trees and blossums. Does this hold true for a tree like an arbavitae that has no real blossum?

Thanks,
Dave

Answer
Dave,

The problem with most oils is that they can damage the cell walls of arborvitae and some other fan leafed evergreens. This phytotoxic reaction occurs if the plants are sprayed too heavily with too high a rate of oil.

The only oil that I can recommend to use is either neem oil or a food quality vegetable oil. These can be used when the temperatures are below 70 degrees.

Good luck,
Ed Gulliksen