Mildew on delphinium help please

I have several dwarf delphiniums, newly planted this year, all of which have flowered well. One, 'Blue Fountain' which has broad leaves, I notice has developed mildew on the leaves and I'd like to know what I should do.

I have seen that it's possible to treat mildew with a 'home made' fungicide made with baking soda or another with milk - but I'm wondering whether it would be better to buy a proprietary product? Presumably it would be better to treat the plants now before they die back and over-winter with the disease?

My other question is, one book I have says 'spray infected leaves with water to remove spores, before treating' although another says, 'before treating, carefully remove all infected leaves so as not to contaminate the surrounding soil' Which is correct?

 

Ah, the dreaded mildew. Here's what the RHS says about it http://www.rhs.org.uk/advice/profiles0800/powdery_mildews.asp

I would use a proprietary product although I've never found a total solution to mildew. You only defeat it for a while and then it'll be back. Some plants seem to be "mildew magnets" and delphiniums are very susceptible, I'm afraid. At least you can take comfort that it's late in the season. You've done well to get your plants this far.

 

Thank you Flinty - I've had a look, it suggests cutting out the infected foliage ... which in my case amounts to cutting the whole plant away! A proprietary solution first m'thinks.

 

I visited Hampton Court yesterday, my favourite historical place in the south of England, and took a couple of guided tours around the gardens which were looking fabulous for the time of year. Our guide was a charming lady who has the main responsibility for looking after the famous Great Vine planted in 1768.

In a quiet moment, I asked her how she treated mildew and she said 1) deal with it as soon as you see it and 2) try powdered sulphur. So that's what I'm going to try next time I see those tell-tale grey patches.