I have over 700 varieties of plants on 2.5 acres, including many fruiting trees, vines, canes, and their relatives e.g. roses. I am surrounded by unmanaged fruit trees in this rural neighbour. Thus lots of pest issues: pear slug, tent caterpiller, aphids, scale, etc. I need help finding a list of plants which I should NOT allow the spray to hit. e.g. I know about hazelnuts, what other plants? I know to avoid ponds and open water, any other landscape things? Specific information will be great also direction to websites would be terrific. Thanks to all for you input. Kris
The usual rule with dormant oil/lime sulphur spray is if you can see any green on the plant don't use it. eg if the buds have begun to swell then you have more chance of doing damage to the plant by spraying the oil than leaving it alone. My grandfather always told me not to try to spray maples as they don't go completely dormant in certain climates. Well I grew up in the southern hemisphere where the winters were about as bad as they have been here in Vancouver this year. so that addage may also work here. might not!! If you have not done any spraying yet I would leave it and deal with the problems organically in spring and summer Pierrot
Hi Pierrot, Thanks for that last post. Here in Spokane you used to be safe if you sprayed anytime in January or February, but we have already had temps in the 40'sF(5-10C). Never thought of looking for the expansion of the buds but always looked to the temperature for my time to spray. But after this will follow your's and your father's advice. Sounds like a good rule of thumb to me. Harry
For fruit trees, the current best timing for oil plus lime sulphur is after the trees have broken dormancy. For apples and pears, bud stage 4-5 is now the recommended timing- as the leaves begin to unfurl. I have been using this timing for over 10 years with no damage and good powdery mildew control. I have never used lime sulphur on ornamental plants; they may indeed be more susceptible to burn.
