What is a Dormant Oil Spray

Many insects such as scale, mites, fruit leaf rollers and whiteflies lay eggs in trees and shrubs in the fall. In the spring these eggs hatch and produce larvae. The larvae begin feeding on the plant and cause significant damage.

A dormant oil spray is a horticultural oil that is mixed with water and then broadcast sprayed on trees and shrubs. The dormant oil either suffocates the insect by blocking the breathing pores or penetrates and destroys the cells of insects and mites that are exposed to it.

Dormant oils prevent significant damage from being done to your trees once the larvae hatch. An additional benefit is that they are less toxic to beneficial insects such as lady bugs than other types of insecticides.

When to apply Dormant Oil to Trees and Shrubs

You want to apply dormant oils to trees and shrubs when the plants are dormant. Late winter/early spring is the best time to apply. The application should be made when it is at least 40 degrees outside so you don’t risk the application freezing before it dries. You also don’t want it to be too hot when you apply the oil. Typically it shouldn’t be over 70 degrees.

For the ideal results you should apply the dormant oil treatment as close to the time the trees are going to bud out without applying it when they are already budding out/blooming. If you apply the treatment too early some of the residual will wear off before the insects are beginning to hatch. On the other hand if you apply it too late it can damage the new growth on the tree.

Can I Apply the Treatment Myself

A dormant oil application is one that you can do yourself if your trees are small enough. You want to make sure that you are careful to mix according to the label and to follow the printed directions. You also want to ensure that you wear the appropriate protective clothing. Small trees can be treated with a handheld or backpack sprayer. If you have larger trees, or are worried about making the application, we would love to visit with you! Our certified technicians can take a look at your trees to see what they would recommend specifically for your property. Trees are a valuable asset and we want to do everything we can to help you protect them. To learn more about other ways we can help protect your trees, click here.