Wake Up Your Fruit Trees – Time for Dormant Oil Sprays

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

There are several 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 essential 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 are easy to see this time of year because there are 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 oval or circular shells. 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 infestations of scale insects 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 the application may be delayed up to the green tip stage. Temperatures need to be at least 40 degrees so the spray has a chance to dry before freezing. If the spray does freeze before it dries, plant injury can occur. Applying the spray in the morning will help ensure 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 and out of control, and you don’t know where to begin, stop by the Extension office and pick up a pruning publication. This publication offers step-by-step instructions for pruning overgrown trees and includes nice diagrams.

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