I have a similar problem but can't get a straight answer. They seem to prefer OGRs.

They are called tripes (rose worm) and they are evil. I lost about 20 roses to them last year before my killing rampage. I used grub killer to help with the larval stage and it seemed to help my epidemic.
Good luck

They could be any number of caterpiller, larvae, etc... without pics and more info it would be difficult to make an exact ID. I simply pinch them between my fingers when I find them.

They are probably some type of sawfly larvae, at least that is what I get here. The ones I typically get are green with whitish spots down the length of their body.

Sawflies are a small non-stinging type of wasp. Adult sawflies are not a problem, but the larvae are. Sawfly larvae are also called Roseslugs. They feed from May to September for 2-3 weeks when they are in larval stage, and then they change into adult flies and the feeding stops. The reason they are called roseslugs because of their slug-like appearance. The larvae also resemble caterpillars, but they are not true caterpillars.

There are several types of sawflies that attack roses as larvae.

The bristly roseslug is a major pest on roses. The larvae are pale green, with a brownish-orange head and very small, bristlelike hairs. They skeletonize the leaf from the underside when small, and then chew holes through the leaf as they enlarge.

The curled rose sawfly occurs in lesser numbers, but each one can cause relatively substantial damage. The curled rose sawfly larvae skeletonize leaves when small and eat the whole leaf, except the main vein, when large. To make matters worse, when they pupate they bore into the pith of twigs, killing portions of the twig and opening it up for fungal infections. The larva has a yellowish head with black eye spots, and a pastel green body with white dots down the length of it.

The roseslug is the third type of sawfly to occur on roses. It looks somewhat similar to the bristly roseslug, but lacks the hairs. It skeletonizes the upper surface of a leaf.

Easiest way to treat them, is to mechanically pluck them off and squish them. If the damage is widespread across many rose bushes in your garden and a lot of damage is being sustained, chemical control should be considered. Just about any contact insecticide labeled for use on roses will kill the roseslugs. Try to use the least toxic one possible, because you don't want to kill beneficial insects in your garden.

Many people use BT to kill them. I am not sure if that is used in a no spray garden or not, but it seems to be the least toxic of chemicals.

Matt, thanks for the great description. I just call all of them bud worms, knowing that they are not worms, but caterpillars.

Sammy

the correct term would be larvae, not caterpillers or worms.

Or we can just call them Rose Slugs like they have been called for a long long time. :>)

Take a look at the following for pictures, explanations about rose bud eaters and rose slugs among a whole bevy of obnoxious rose pests

I was sitting outside and noticed the leaves on my rose bush had been eaten away by something. I then noticed these little green looking caterpillar looking worms on some of the leaves. Upon closer inspection I saw multiple critters all over the bush as well as many had bored into the stems of the plant and the ground as well was covered in them. I found in the garage some rosebush spray. I emptied the container on the bush. I took the empty spray container and started gently hitting the bush knocking them to the ground. I looked on the ground to find a gazillion of them crawling all over the place. I don't know when I knocked the bush these all fell off or there were more on the ground. I took the hose and attempted to drown the stupid worms. I just went out and checked to see if I saw any movement. As I shined the flashlight I didn't see any movement. So not sure if what I did worked? I have to be careful of what I use seeing I have a 3 year old grand daughter living in the house whom has A-L-L Leukemia. I found flour in my cupboard so I just sprinkled the entire flour container on the rosebush. I will let it sit for a day or more because of all the water I put on the plant tonight. I am sure the infestation I am experiencing is due to my lack of caring for the bush this time last year seeing my grand daughter was diagnosed in April and taking care of my garden was not a high priority. Tomorrow going to get more spray and after I have established the worms won't crawl on my feet or anywhere near me, I will then prune the bush back down, hoping it comes back. I know I looked at the bush a week ago because this year we actually were able to have a birthday party for my grand daughter on the 21st of May. The bush was not being devoured by these critters. Bugs, worms whatever they are I don't want them anywhere near this house because of my grand daughter and her special circumstances.

I have success with BT. It is a Biological Insecticide. It is called "organic" I am not sure about its use around your granddaughter! The best defense IMO is a rose garden walk a couple times a week and a close look at buds. I lost my whole second set of blooms to tiny green caterpillars this year so I an on a constant vigil.

BT is the best thing to use against caterpillars (moth and butterfly larvae) but it does not affect the similar-looking sawfly larvae. Spinosad products and insecticidal soap work on both kinds.

Yes, I get them. They are soft bodied and the same color as the smaller rose slugs that you find in early summer on bottoms of leaves. They are quite a bit larger but still eat their way up then wrap themselves around a bud and devour it. They keep going until a predator or I discover it.