Powdery Mildew

Having a bad year with Powdery Mildew, spraying with Rose Guard which seems to control it and the bugs that were hanging about. I suspect I have one Rose in my midst that is the cause of the problem, if it doesn't desist its for the chop. I also have Dr Huey bobbing up which is totally covered in Powdery Mildew, its also in for the chop.

Dr Huey is a mildew magnet which is a shame because it is such a nice rose when it looks good. I learnt one trick against powdery mildew which is totally organic and seems to work (but it is a catch-22 treatment). PM hates moisture and can't survive when the plant is wet. Problem is, black spot LOVES it. You can get around this by going out early in the morning and giving your roses a thorough drenching so they have the rest of the day to dry out. You don't have to do this all the time (here anyway) because PM is really only a problem when the days are warm and the nights are cool. Once summer kicks in for real here and the nights are also warm PM subsides. PM is not generally caused by an infected plant because every rose has a certain amount of natural resistance bred into it and PM spores are airborne and pretty much everywhere. If you have PM prone varieties you either shovel prune them or try and combat it. If you are not worried about using chemicals there is a fungicide called Fongarid which is systemic that seems to do a pretty good job. You spray is on the soil and leaves allowing the rose to take it up. When the spores infect the tissue it is killed off by the Fongarid. You only apply it once every three months too. Most/all your roses are in pots so you should be able to really target each pot with a measured dose if this is something you wanted to try. I do the water drenching thing. You have to do it pretty regularly but it does work. If I didn't spend so much time surfing the net maybe it would be easier for me to get up early and water down my roses

Would Fongarid work for black spot ???

Fongarid is a general purpose systemic fungicide so it may work well for BS too.

Thanks, I'll get some then
Val

Thanks Tas, I have found that Rose Guard can knock new shoots around so will try Fongarid. We are down to 155 litres per day so water is at a premium even with the grey water I save.

I generally just use Mancozeb when I spray. It's been so windy and rainy here lately that mildew has been a non-issue here this year. Black spot on the other hand is a PITA!

I don't get it! We have had showery weather here for the past month and I have mildew!! It is so wet here I have trouble weeding.
Maybe the water has to be permanently on the leaves to work? Like grow them in a bath? Or misting system?
My new Brass Band is sporting mildew on its new shoots which is a disappointment.

Yes I have quite a lot of BS and just minor PM

A good drenching each morning so that the water is dripping off it should be enough... BUT I should have also said that some roses are so prone to mildew that they will get it no matter what you try!

tell me about it, I think Lorraine Lee in that cat.