I have two questions about apple tree care. 1- when and with what should I spray the tree? a green solution. 2- the tree has been dropping quite a lot of yellow leaves. We had a thunder storms over the last few weeks, so I thought that this would be normal. But this week there seems to be even more.
Spray program needed, if any, depends on what particular pests and diseases you have there. Numerous leaves yellowing and dropping would not be caused by thunderstorms, would be indication of some cultural problem. What to do about it depends on what it is. Local independent garden center, agricultural office (down here we have USDA Cooperative Extension Service branch offices in most counties, with many states having Extension Service web sites as well) or other regionally oriented cultural information source should be tried for assistance.
Many thanks for your suggestions Ron B., I shall get in touch with Agriculture Canada and a local Nursery.