Answer: When to prune depends on what kind of roses you are growing. Hybrid tea roses are carefully pruned in the early spring and landscape shrub roses are cut back hard in the early spring, but old garden roses are usually not pruned until after they bloom, for example. In any case you would not be pruning any roses now in the fall.
What to spray would depend entirely on which pest you have. You might wish to work with your local chapter of the Canadian Rose Society for help in identifying and treating pests on your roses. They may also be able to help you with determining how to best prune your roses.
In the meantime, their web site offers much practical advice. The American Rose Society web site also offers lots of care information you may find helpful.
I hope this helps you get started in learning about your roses.
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