I use Rose Clear Ultra.

Hi there are a couple things I would do in case of mildew on Roses.

1) Increase the amount of sunlight the roses receive. Sunlight naturally repels mildew and roses love Sunlight, the more the better.

2) Improve air circulation around the roses. Clear away all weeds and debris so that air circulates around the plant continuously. Also, cut away dead and old canes that aren't performing. Open up the plant to fresh air and let sunlight get into the middle of the plant.

3) Water roots only, and not the leaves. Keep leaves dry as possible, only water the roots. Water early in the day.

Thankyou for you help I dont know alot Im just learning

Oddly, hosing the leaves down early in the morning often kills the spores as they sprout--another one of those counterintuitive cures.