Different brands have different dilution rates, so you need to read the bottle directions carefully to determine the rate appropriate to the plant and brand. If you have lost the directions, just look up the brand online, and they usually can provide a copy of the label, usually as a pdf file.

Talking neem, does anyone know if you can use the oil in an oil burner? i used to use the neem incense sticks as air fresheners but can't get them any more.

I am interested too as I've just sent off for some for my sooty mold.

Sorry, Ostrich! I didn't think of neem oil not packaged for garden use! I'll check the concentration and directions of the stuff I sell at work today, and hot up the calculator! :)

My neem oil arrived today courtesy of Amazon and I had to look up the ratios. 1 tsp neem oil, 1/3 tsp soap or detergent mixed with 1 litre of warm water. (Monty Don says you can use wash up liquid).

Thanks, Cammomile! That's what my calculations show, too, if you have pure neem oil, Ostrich.

Thank you Cammomile & Tugbrethi....that concentration I think is quite low, but that is what I will use & fingers crossed will not have the problem this year. If Monty says ok then who am I to argue!!!
I am also going to spray the ground around the affected trees (those affected last year) and see if that might help.

I'm still trudging through cleaning off the leaves and although the Camelia is only about 4ft tall it's taking forever. Hopefully I can start spraying under the leaves after that's done.