Sprayed today with spinosad, sticker, and summer oil (3T/gallon of bonide horticultural oil) and noticed a bit of powdery mildew. I’d like to go back and hit those spots with sulphur but don’t know how long to wait. It’s been hot and will be for a few more days.
Couple of years later I’m wondering the same thing… anybody?
Reason: I sprayed horticultural oil last week on my trees. Today I sprayed sulphur thinking it should be fine since we had 0.75 inch of rain since then. But now I’m worried.
Sorry to say I still don’t really know- I’ve just made a point of waiting a month between the two of them. In your case that doesn’t help, and the proof will be in the pudding. Sorry you’re being the guinea pig here!