I do use Neem and am quite happy with the control I get. I've also heard about mixing baking soda, baby oil and water but haven't I tried it and don't know what the proportions would be. Apparently the baking soda makes the leaves too acidic for fungus to grow and the baby oil helps the mixture stick to the leaves. You do have to be careful though--too much baking soda will burn the leaves.

The Cornell formula is far superior to neem oil for black spot on roses.

I use wettable sulphur.

What is wettable sulphur, where do you get it, and how do you use it? Is it like lime sulphur?

Wettable sulphur is micronized (?) elemental sulphur that can be dissolved in water and then sprayed on the roses. Sulphur powder is also used, but spraying it is a lot easier. It is different from lime sulphur. It is sprayed in the growing season, and is not used as dormant spray.

I don't know where you can buy it in the US. I think it is sold under the Bonide brand?

Rob

You can get wettable sulfur at any decent nursery. It works ok, but not great.

What is cornell formula? Sorry if this seems a silly question. Thanks,