Use baking soda with a surfactant to make it adhere (dishwashing soap).
Mary
Gail Larkin wrote:
> Tia - sorry to say the sulfur spray is only for dormant season (when the plant > is leafless) - it is too strong/burns the leaves in the summer even in the > dilute form. > > Jaykhill wrote: > > > Is a sulfur spray considered a reasonable organic solution to treating black > > spot on roses? I have one bush which is hit so hard it would be virtually > > leafless if I cut off each spotted leaf? > > > > TIA > > > > John Cahill, Mt. Vernon, VA