Probably Rose Slug. Look on the undersides of the affected leaves, and odds are you will find small green worms near the white spots.

Just fold the leaf over the Rose slug and squish. :)

Baby rose slugs do not make holes entirely through the rose leaves. They are not large enough yet to do so, and can only eat the leaf tissue on one side of the leaf, leaving an opaque 'window,' where they are, then they move on and start a 'window,' elsewhere on that leaf or on an adjacent leaf. As the Rose slug grows, their mouths become large enough so they can successfully make complete, see-through holes right through the rose's leaf.

Of course, rose slugs are not slugs at all, but are the larvae, caterpillars, of an insect, the saw fly. Rose slugs, if left unchecked, can do considerable damage, almost making all the leaves on a bush lace like in appearance with their innumerable holes and opaque 'windows,' rendering such damaged leaves useless for photosynthesis.

Moses

Rosecanadian, what an ingenius idea,lol I dont even have to get my hands dirty.

Thanks everyone for your help. I had an inkling this might have been the dreaded rose slug. At least I’ve caught it early.

I have found rose slug free bushes growing next to infested ones. Does the female saw fly detect a possible natural rose bush produced insect repellent present in some varieties that is absent or diminished in other varieties, thus depositing her eggs on the least self protecting one's only? Or do the eggs laid on strongly self protected rose varieties hatch, but the baby slugs die after just one small mouthful of leaf?

Moses

So I cut out all the leaves that were affected and also sprayed with dishsoap and water. The weird part is that I couldn't find any worms, which makes me nervous that one might be hanging out that I can't see and will do more damage. I also sprayed the plant with lots of water from below the leaves.

Jo,

The amount of damage shown in your photos actually is pretty light. If the level of foliage damage was the same as in the original photos when you stripped them, I respectfully say that stripping them was unnecessary. In that original photo stage the leaves still could easily feed and build up the vigor of the bush. By all means though, spray with an effective method to control further damage.

It has not been easy for me to find those little chewing caterpillars under the leaves. Only rarely am I successful in my search for them. I guess they hide themselves when they see me coming! 😁

Moses

Thanks Moses! It's mostly concentrated at the bottom of the bush. Glad to hear I'm not the only one who has had difficulty finding these critters.

The caterpillars are extremely small and hard to find! I've noticed much more damage with them on roses close to the walls of my house, whether in the ground or potted. I've always thought they might be more sheltered from the notice of my many hungry birds there.

Susan, that’s definitely possible. My roses are closer to my house as well.

Totally off topic but i noticed you’re from Santa Barbara, such a beautiful place. I visited there 20 years ago, cant believe it’s been that long! I would love to go back.

Jo, that's interesting that you're noticing more rose slug damage closer to your house too, and in such a different climate from mine. It's not that they don't attack roses in the open, but over the past 20 years or so, I've noticed a definite, significant trend! I have several baker's racks next to the house that I put potted cuttings on as they grow up, and I often move them to get away from the wall and the rose slugs. Not possible to move a rose in the ground, but I find those to be more forgiving in that regard.

I moved to Santa Barbara in 1987, after living in Pasadena for the first 31 years of my life. I much prefer the climate in Santa Barbara :-D