Fruit Tree Dormant Oil Application

February brought us above normal temperatures. I’ve heard the frogs signing on several days, which is always a welcome sound to my ears because I know spring is near! When the nice, warm days grace us in March, make time to apply a dormant oil on your fruit trees.

There are a number of dormant sprays used on fruit trees and other plants to control various diseases and insects. However, a dormant oil spray is designed to control scale insects, aphids and mites. Just like the name implies, dormant oils are applied before the tree begins to bud. Dormant oil sprays are important because some pests attack before visible growth even begins. If you have a problem with scale, now is the time to start watching the weather and look for an opportunity to spray.

Scale insects can be seen easily this time of year since there a no leaves. Scale insects are easily overlooked because they are small and immobile most of their lives, and they do not resemble most other insects. Many of them resemble small shells that are oval or circular. Coloring varies but can include white, tan and brown. Plants that should be inspected for scales include apple, pear, other fruit trees, lilac, crabapple, oak, ash, elm, maple, arborvitae, juniper, pine, spruce, euonymus and yew.

Plants are not harmed if only a few scales are present, but scale population can increase dramatically during the growing season. Heavy scale infestations can damage fruit crops, destroy branches and kill entire plants.

Normally sprays should be applied around March 1, especially with peaches and nectarines. Apples are tougher and application may be delayed up to the green tip stage. Temperatures need to be at least 40 degrees so spray has a chance to dry before freezing. If the spray does freeze before it dries, plant injury can occur. Applying the spray during the morning will help insure that it dries properly. It is much easier to achieve good spray coverage if the tree is pruned before spraying.

The Extension office has several publications outlining the fruit spray schedule for the entire growing season.

Now is an excellent time to prune. Pruning can be done in March. Prune on days when the temperature is above 20 degrees to prevent injury. Prune older trees first because older, larger wood tolerates lower temperatures than young trees with small diameter wood.


If your trees are overgrown, out of control and you just don’t know where to begin, stop by the Extension office and pick up a pruning publication. This publication offers step-by-step instructions on pruning overgrown trees and it also has nice diagrams.


Krista Harding is a K-State Research and Extension Horticulture agent assigned to Southwind District.  She may be reached at [email protected] or 620-244-3826.


K-State Research and Extension is an equal opportunity provider and employer.


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