Protect your woody shrubs and trees from insects by using a dormant oil spray. Dormant oil will kill exposed insects by over coating and suffocating them. It will also cover their eggs and prevent them from hatching.
Dormant oils are typically refined from petroleum oil and contain an emulsifier to allow the oil to mix with water. Since they are petroleum based, they have a lower level of toxicity as opposed to other solutions which kill the insects by poisoning them.
Paul Weaver, certified arborist who handles all of our tree and shrub pest control, says, “Dormant oil is a wide-range insecticide, so it covers most pests out there.”
In our area of the country, some of the more common insects that are targeted are Scale, Spider Mites, and Aphids. They also are effective in addressing Gall issues.
It’s best to treat your trees and shrubs in late February or early March before they leaf out. Weaver says that he typically treats burning bush, oak, spruce, junipers, flowering crabapples, locust trees and holly among others.