Posted: 10/08/2015 at 10:37
There are various Daconil (well, Chlorothalonil-based) products for different purposes - anti-fungal for toms and spuds, treatment for lawns, etc. The anti-fungal product is composed of 29% Chlorothalonil. That's the minimum figure. The other products with lower percentages aren't suitable.
I've been hunting around online. You can get it in the UK in domestic quantities but it looks like it's sourced from the States so I hate to think what the postage might be. It's not cheap, never has been, but it's 1 tbsp of concentrate per gallon of water so it lasts. I'll keep looking.