I just cut these off my plant. Is it a disease?
That does not look like black spot. Possibly rose slugs?
Thank you. I'll have to look up some info on that.
No, that's not black spot. It does not look like any kind of disease. If it's an insect you need to find the bug responsible before you use any type of insecticide. Not all insecticides work on all bugs. If you spray the wrong one you could kill off the good bugs and create an even worse problem.
Where were these leaves on the plant? Is it possible that they just got damaged by something? Are there more areas where it's happening?
Actually you could of left them on the rose bush as it does look like insect damage and not blackspot.
It will not hurt anything its just an eye-sore to some people.
Look for small greenish looking worms on the underside of the leaves. Our rose slugs get about 1 inch long when mature.
Kansas girl, the pic below is blackspot on rose leaves.
Your damage was caused by something else...
Thank you for the photo and information. My leaves definitely don't look like that. All of the leaves up top are perfectly fine. There are a few more areas on the lower ones towards the middle that look like this. I looked around and didn't see a bug. Can they dig into the soil? This is a new plant and I have to repot it into one of my own containers (I was going to wait until closer to Mother's Day). Maybe we left the little critter back at the nursery?
Just looks like a rose leaf that's been a little beat up at the nursery to me.
Unless it gets worse and continues to spread I agree with the professor, it looks like older leaves that were damaged somehow. Being toward the bottom center of the plant means these are probably some of the oldest leaves on there and who knows what they've been through already.