Extension

Gardeners may not have a lot going on in the landscape during this time of year but applying dormant oil to fruit trees is a task that needs to be done. Dormant oils control scale insects, aphids and mites that are overwintering on the trees.

 

Dormant oil should be applied in the late winter or early spring when the temperature is between 40 and 70 degrees Fahrenheit to suffocate insects and their eggs that are nesting in the branches. Be sure to check the weather to ensure a planned application won’t be followed by freezing temperatures or rain for a few days.

 

Although this process won’t completely eliminate these pesky pests, it’s the most effective method. Applying the spray now should leave gardeners with lesser issue of pest control to tackle later in the season.

 

What exactly is dormant oil? It’s an oil-based product designed for use on fruit trees. It has surfactants mixed in to enable it to be mixed with water for easy application. When applied, this mixture penetrates into the surface of the insect’s hard outer shell and kills it.

 

Applications should be made to apples, pears, plums, pecans and crabapples. Peaches, nectarines and apricots often do not require dormant oil sprays, but if certain insect pests have been an issue in the past, it could be beneficial. Dormant oils also can be beneficial for shade trees and woody ornamentals. Consult the label before application to make sure the plant is listed. Some plants are sensitive to dormant oil applications.

 

Start with the uppermost branches and work your way down. Move around the tree to ensure the spray gets into all crevices.

 

Gardeners with annuals planted near plants targeted for an application of dormant oil should cover the annuals before spraying as the dormant oil will kill the annuals. Although it’s too early for transplanting this time of year, gardeners who are hardening off marigolds, snapdragons and other flowers, should cover or remove them from the area.

 

Check the local weather before applying dormant oils. Make sure temperature is at least 40 degrees Fahrenheit and will stay that way for a minimum of 24 hours. Also, choose a time when no rain or high winds are predicted.

 

Aside from being relatively inexpensive, dormant oil is less toxic than other sprays used to control these pests, and there’s little toxicity to birds and mammals. Getting a good coat of dormant oil on fruit trees will help avoid a big pest infestation later in the year.