Dormant Spraying of Fruit Trees

What Are Dormant Sprays?

A dormant spray is so called because it is applied when the plants and trees are in their dormant, resting stage, during the winter. Dormant sprays effectively kill fungus and diseases that are trapped and growing in the bark, cracks and crevices of your fruit trees. Dormant oil is used to basically suffocate insects and eggs of pests in your tree before the pests wake up from their winter sleep.
Dormant sprays are usually combined with a dormant oil for easy application, since both can be applied at the same time. We carry dormant oils and sprays in our Garden Center.   Be sure to follow the mixing instructions exactly, as too much or too strong a solution will harm your fruit tree as much as the diseases and pests you are trying to get rid of will.

When to Use Dormant Sprays?

Dormant sprays need to be applied when the leaves are off the fruit tree.  These sprays should be used two to three times during the winter for maximum success.  The first spraying should be in the late fall if possible. This fall spraying is like a protective coat for your tree. It inhibits disease spores from being blown by the wind to unaffected trees and plants.Choose a windless, dry day when rain is not in the immediate forecast.

Since winters in this area are on the mild side, you should spray your fruit trees again around Christmas. Again, select a day when the wind is not blowing and there is no threat of rain in the forecast for at least 24 hrs or more. This midwinter dormant spray application is the least critical, and, therefore, if the weather doesn’t cooperate it can be skipped.

The final, and most important, application of dormant spray and oil should be in the late winter or early spring. In this area, Mid January to February is the perfect time. The key is to apply this spray before your fruit tree has formed buds. The beginning of leaf formation is the ideal time, but if your fruit tree has already formed its flowering buds, it will be too late. Spraying dormant spray when your fruit tree is flowering will kill the bees that are there to pollinate your tree and the result will be little or no fruit.

How to Apply?

  • Be sure to follow the manufacturer’s recommendations when using these products.
  • Apply this spray under pressure with a pump sprayer, or with a hose-end sprayer, covering the areas two times. Complete coverage is required for effective control of all over-wintering pests.
  • Keep your spraying to plants which have had infestations during the prior year!  You don’t want to kill any beneficial insects that may be on other plants.
  • Be careful about exposing evergreens to the spray which is strong and can cause damage.
  • The use of a dormant oil mixture may destroy annual flowers growing under or near plants being treated.  Completely cover any tender vegetation BEFORE spraying.
  • Fungus spores can also over-winter on fallen leaves.  This is why it is especially important to rake and dispose of leaves if you know you have a disease problem.