What is being eaten on your roses, leaves or buds? Sawfly larvae, once to a certain stage, will eat large rounded parts of leaves until little is left. Smaller larvae may pit the leaves.

Caterpillars are technically the larvae of butterflies and moths. Fly larvae are referred to as maggots, although the term sawfly larvae is in wider use.

Thank you, Larry Gene. It is the leaves that are being eaten, the new growth.
Treatment?

I have not had this type of caterpillar but I've had good results with other types with the Bacillus thuringiensis spray.

Please post pictures so that awe know what sort of "eaten" is occurring.

Picture is a good idea. My experience with sawfly larvae is they will eat ANY leaf, never mind the new growth!

In a google image search for sawfly+larva+roses see if the images with curved areas of leaves eaten are similar to what you have going on. Many of the other google images may be something else.

This is the damage that is being done. This morning I hand-picked a few of the worms again, they are always on the back side of the leaf, usually only one instead of several, and they are less than half an inch long. The damage is also always on top of the bush in the new growth. The flower buds are undamaged. I have had roses for over 40 years and have never had this kind of a problem.

It is not inconsistent with sawfly damage, but it could be a number of other pests also. Sawfly damage is usually pretty extensive, your damage could just be from some moth larvae.

Also, the sawfly larva I had did not care which side of the leaf they ate from, and they are active during the day. Many other caterpillars feed at night.

Sawfly larvae are not true caterpillars, and so are not affected by Bacillus thuringiensis (Bt).

I have pine sawfly larvae on my mugo pines. A quick spray with a 50/50 mix of isopropyl alcohol and water (with a bit of mild dishwashing liquid as a sticker) kills them dead!

The same spray kills mealy worms.

I haven't used it on roses, but I don't think it would damage the leaves.