helen
Newly Registered
Posts: 5
Joined: Sun Jun 06, 2004 8:54 am

Black spots on roses.

I have blackspots on my roses, even on new shoots and leaves. What causes this? and what can I do about it?

I've tried insecticide, fungicide but it still comes back. I live on a busy main road, could polution from passing traffic cause this? or could I be using the rong soil?

The Helpful Gardener
Mod
Posts: 7491
Joined: Mon Feb 09, 2004 9:17 pm
Location: Colchester, CT

No black spot is a very common fungal disease that is prevalent on hybrid tea roses especially; I'm guessing if I looked at the list of roses you are growing they're mostly old guard types like Peace, Mr. Lincoln, JFK and the like. That means VERY diligent care or black spot will show up for sure.

Are you using one of those one bottle kills-it-all type things? Those don't do a good job of any of them, with the exception of neem oil, a natural product we think highly of around here. Without a general locale, it's hard for me to pinpoint any other issues, but I doubt traffic has anything to do with it; it's fungal almost for sure...

kevinschoppe
Cool Member
Posts: 90
Joined: Sat Apr 30, 2005 10:54 pm
Location: Zone 8A Texas Gulf Coast

The Black spots are called Displocarpon Rosae, and I treat mine with Ortho Rose Pride Rose & Shrub Diease Control.

The spots spread when you water your plants, it is a fungus, and it spreads by the air too. What you can do is to cut off the affected leaves, burn them, spray the affected areas. Keep you clipping shears in a solution of clorex & water to avoid cross infection to other plants.

I hope this works, let us know....

Thanks-
Kevin

The Helpful Gardener
Mod
Posts: 7491
Joined: Mon Feb 09, 2004 9:17 pm
Location: Colchester, CT

Thanks Kevin.



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