Is it black spot diease or not?
Previously this season I had a lot of yellow leaves. Now there are more yellow leaves but half the yellow leaf has turned brown. Once before I had real brown spots but this now is different. What do you think?
When my roses get yellow leaves, my first thought is spider mites. Have you checked for them? You'll know them by their webs. 
Black spot looks like what it's called. The leaves develop black/dark brown spots. The leaves also turn yellow and dry looking over time. Black spot is a fungal disease.
If you posted pictures, it would help us evaluate the problem you're experiencing.
Here is information about how to post pictures:
https://www.helpfulgardener.com/forum/viewtopic.php?t=3724
Black spot looks like what it's called. The leaves develop black/dark brown spots. The leaves also turn yellow and dry looking over time. Black spot is a fungal disease.
If you posted pictures, it would help us evaluate the problem you're experiencing.
Here is information about how to post pictures:
https://www.helpfulgardener.com/forum/viewtopic.php?t=3724
Last edited by Kisal on Sat Jun 20, 2009 1:58 am, edited 1 time in total.
Without a photo, it's hard to tell, but black spot really is black. My roses will develop black spots right in the middle of otherwise green (or at least green-ish) leaves.
My rose leaves turn yellow and/or brown when I've let them get too dry or (incorrectly) watered them and the leaves still had droplets when direct sun hit them *and* it was a hot day.
I'll see if I can scare up a photo of black spot.
Back shortly.
Cynthia H.
Sunset Zone 17, USDA Zone 9
My rose leaves turn yellow and/or brown when I've let them get too dry or (incorrectly) watered them and the leaves still had droplets when direct sun hit them *and* it was a hot day.
I'll see if I can scare up a photo of black spot.
Back shortly.
Cynthia H.
Sunset Zone 17, USDA Zone 9
Well, here are three photos from the U. of Arkansas:
https://www.aragriculture.com/diseases/image_library/tree_ornamental/rose/black_spot.htm
but the spots appear, on my monitor at least, to be brown. My roses clearly haven't read the book
and insist on displaying much darker spots. My search phrase was
"black spot" roses photo
so you can find other diagnostic photos and, perhaps, find an exact match for your roses. (No digital camera in this house, so I have to "reverse engineer" a lot of stuff--like these rose photos, for example!)
Cynthia
https://www.aragriculture.com/diseases/image_library/tree_ornamental/rose/black_spot.htm
but the spots appear, on my monitor at least, to be brown. My roses clearly haven't read the book
and insist on displaying much darker spots. My search phrase was"black spot" roses photo
so you can find other diagnostic photos and, perhaps, find an exact match for your roses. (No digital camera in this house, so I have to "reverse engineer" a lot of stuff--like these rose photos, for example!
)Cynthia