During the winter insects & trees will go into their dormant stage, but before they do, the insects will lay their eggs on the trees branches & leaves so when spring arrives they hatch and eat the new growth on the trees.

Sierra Pest Control Dormant Trees

Dormant Trees

One way to prevent these pests from hatching & devouring a healthy tree is by spraying Dormant Oil on the exterior of the tree which will cover all of the exposed insect eggs causing them to suffocate so they will not survive by the time spring arrives.

In order to spray Dormant Oil on the trees temperatures must be above 50 degrees F. and the tree must still be in its dormant stage, usually from Nov-March.

Even though Dormant Oil is petroleum based its actually a highly refined oil designed for trees, its not a motor oil.