I have had sooty mould on my Star Jasmine for the past two years. I've researched the causes and the remedy seems to be to spray the plant to get rid of the infestation causing the residue on the leaves. Various websites suggest using Neem oil but I've yet to find a commercially produced product to use. Has anyone had the same problem and resolved it? I know you can wash the leaves but it's exhausting and is only a short term solution. Ideas please!