Burnett: Optimum time for dormant spraying is now—early April
Even though some of our fellow Canadians in other parts of this country are experiencing the icy grip of winter still breathing a cold chill down their backs it looks as if we here in the Okanagan are seeing some signs of spring.
Crocus and snowdrops are up in many areas and the forsythia is just about to burst forth its golden exhibition.
And now is the time to think about getting the dormant spray on roses, fruit trees and small fruits.
For some gardeners it is just as much a part of the process as pruning, planting, fertilizing and harvest while others either are unfamiliar with the benefits and never take the time to do it or just put it off until it is too late.
Applying a dormant spray at the appropriate time each spring has many benefits and I highly recommend it however it is not a panacea for everything.
Dormant sprays consist of two products combined to protect your trees and shrubs from certain insects and diseases. The ingredients are sold as a “kit” which is available in all gardening outlets. The kit has a one litre bottle of lime sulphur and a 250 ml bottle of mineral oil. When mixed according to the label directions and applied it will control such things such as scale insects, spider mite, overwintering aphids and to some degree leaf rollers if applied at the optimum time.
It will also suppress mildew, black spot and certain other fungal problems most importantly leaf curl on peaches.
The optimum time for application is in early April and even though it is called a dormant spray I recommend waiting until now (late dormancy) for optimum efficacy. In fact I wait until the middle of April to spray my roses and grapes when the buds have already opened and grown an in or two.
With peaches and other fruit trees it is important to avoid spraying while the colour is showing so the blossoms are not harmed.
It is important to note that dormant sprays do not control all insect and disease pests. For instance these sprays have no effect on peach tree borer or any other bark or root borers such as weevils and pine bark beetles.
There is no control of codling moth, walnut husk fly nor cherry fruit fly using the dormant sprays either.
However I still believe using the dormant spray is important in keeping the previously mentioned pests at bay.
In particular it is very affective on grapes for mildew and I even think I have achieved some protection against leaf hopper and erineum mite. It is also very effective for mildew and aphid control on roses.
And, most importantly, it will help prevent the dreaded peach leaf curl which has really been a problem in recent years.
One word of caution; If you have old materials in your garden shed especially if the lime sulphur has been frozen at any time I suggest you invest in a new kit. I used some older material this season and plugged my sprayer up to the point I had to use compressed air to clean it. Not fun.