Hi -- I suspect it's too late to spray my fruit trees with dormant oil here in the Vancouver area. Can anyone confirm that? Not all my fruit trees have leaves yet, but it seems I should have sprayed back in February ...
It isn't an issue of timing. It's an issue of the state of the buds. When the buds start to open, you can no longer spray because the spray will kill the now-revealed parts of the buds' interiors and you will have no flowers - and no apples - that year. As long as the buds have not started to open, you can spray. I sprayed my 4 a few weeks ago, but at least one of them could still have been sprayed (again) a few days ago, when I looked at it last time, if I had wanted to do so, because its buds had not started to open.
Depending on the size of the tree you could spray the trunks only to get some benefit from the dormant oil. I would think that most insects have not started to move yet.
We sprayed yesterday, and believe the timing is just about right or even slightly early. Soccerdad is right, you do not want to use oil once you see the flowerbuds start to open. Green leaf tip (stage 4) is just right for a combo of oil and lime sulfur. If you spray when the tree is completely dormant, the oil may help smother overwintering eggs/larvae of various pests, but the lime sulfur won't help prevent powdery mildew (the main purpose of using it!).
OK, here's some pics of where my trees are at, taken seconds ago. The apple trees are just whips which I have oblique cordoned, and the cherry is an espalierded one. Thanks so much for the feedback.
