Thanks

If its white then its mildew, very common in roses, you need to spray with a fungicide, but I'd recommend you get yourself some Roseclear 3 and a sprayer to mix it in - you will undoubtedly need to re treat at some point in the year, roses being very prone to aphids, mildew and black spot, and Roseclear 3 does both fungal (mildew, black spot) infections and aphid infestations. Note the mix is stronger for fungal treatment than it is for aphid, and Roseclear 3 is systemic, which means the effects last a fortnight and not just 24 hours as with a lot of others.

Thanks for that, I will give it a go!