About Dormant Oil
It’s not just your plants and trees that are dormant this time of year – there are also plenty of dormant bugs on your plants and trees. Before they become active and cause trouble you can kill them by spraying the plant with dormant oil. This thin oil coating smothers the insects and also coats the bark and leaves to prevent bugs from feeding on the plant.
It is especially useful for controlling pests on fruit trees since it aids in killing off the over-wintering insects like aphids, mites and scale.
When to apply dormant oil? Many people spray dormant oil on their fruit trees too early in the season to receive the full benefit of the application.
According to Texas A&M the closer the application can be made prior to buds opening the greater the kill will be. Also, the temperature should be between 40 and 70 degrees for a 24 hour period with no rain during that time.
When spraying ornamental shrubs make sure to cover any annuals nearby since the dormant oil mixture will kill pansies, snapdragons, etc.