Dormant spraying of fruit trees and deciduous shrubs

to prevent the spread of fungal diseases and control harmful insects

Dormant spraying helps to keep destructive insect populations as well as potentially deadly fungal infections under control.
Dormant spray should be applied to all deciduous trees and shrubs which had insect infestations or fungal disease during the prior year.
This is especially important for fruit trees and roses.   

Dormant oil spraying should be done on a clear day when there is little or no breeze. The ideal temperature for application is between 40° and 70° F., preferably temperatures should remain over 50° F. for at least twenty four hours in order to get the oil to spread out over the tree and cover all crooks and crevices.
Complete coverage is required for effective control of all overwintering pests.
Apply this spray under pressure with a pump sprayer, or with a hose- end sprayer two times; when all of the leaves have fallen (late November or early December), and again in early February before buds begin to swell. In some instances, gardeners are successful with only one application during the period of early December through late January. But if the infestation or disease was very bad during the previous season, two sprayings would be the best bet.
For insect control, use Dormant Spray Oil or Volck Oil. These oils will smother insect eggs overwintering in the same places as the fungal spores. Either of these two products can be mixed together with Lime Sulphur for excellent control of insects and disease.
Because these products are oil based, be sure to shake, not stir, them to ensure complete blending.

CAUTION!
It is absolutely essential that you always follow the manufacturer's recommendations when using any chemical product.
Limit your spraying to the plants which have had infestations during the prior year!
Widespread spraying can have the adverse effect of killing many beneficial insects