You could try covering the soil beneath the bushes where they pupate with landscape fabric and encourage birds in your yard. This would both prevent them from emerging and dropping into the soil after feeding on the leaves and provide something that feeds on them . Your ministrations, while beneficial for the general health of the rose which helps it survive predation, will do nothing to discourage insects finding them tasty, unfortunately. I do the above for midge and it has worked fairly well.

My roses are right next to a very busy bird feeder...I keep hoping they will look up from gorging themselves on bird seed to help me out a bit, but no luck so far!

Yes, you're treating them too well. Also, I'm not sure if birds that eat the seed also eat worms and such. What birds visit your feeder? Maybe they're scaring off the sawfly eaters. :-((

OP has already stated a “ strictly leave it alone and nature will take care of it” philosophy is followed, aside from their active squishing of larvae. The active bird feeder, I believe, belongs to a nearby neighbor, if the OP has accurately characterized their ( the OP’s own) practice. Therefore ( so), OP should not be held accountable for the birds good treatment.

I have a question with the sawfly larvae. Last year my Shield Rose had these so would sit outside on my white stool with a measuring cup full of dish detergent and hot water and pick off any I saw and drop them into it. Then when finished pitched the water with them in it them over the wooden fence at the end of our lot onto the other side of the fence. Nothing is present on the other side :D So my query is if a plant has had them say last year would they get them again the following year?? Haven't seen any this year on it. Blaze rose never had any last year now this year it does. Couldn't find that many on it. Have robins, chickadees, etc come out the back. So maybe they too perhaps ate a lot of them of it. Yet the second blaze rose has none on it.

When I've used the "Cornell formula," it seemed to make a big difference -- it worked for maybe 3 or 4 weeks. You have to spray the undersides as well as the tops of leaves and the canes. Other times, I've spent entire weekends hunting, picking, and squishing. The little green horrors are just starting to show up now. Now that my roses are more mature, however, they're not as much of a threat, and last year I mostly ignored them. Good luck.

The Cornell formula is mainly for black spot, yes? I wasn’t aware that it worked as a critter control too

Skr, yes, it's probably the horticultural oil in the formula that works on the sawfly larvae, but because we have plenty of black spot and rust, I've used the Cornell mixture, or some version of it. I was really surprised at how well it seemed to work--I was dealing with literally a slug (or two!) on @75% of the leaves on many of my roses for several years and was spending entire weekend afternoons picking & squishing them. Things seem better now (famous last words) that my roses are more mature and I've seen only a small number so far, but it's early days yet.

Here's an article you might want to read--see in particular the section on insecticides.

http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/insects/sawflies/rose-and-pear-slugs-sawflies.aspx

Thank You for the article...the last picture of a defoliated bush is spot on for what my bushes are looking like!. Do you have any tips on how to help them recover? I can start by spraying to limit further damage but any tips on fertilizers to help?

Between the birds and myself I think we have conquered the sawfly larvae on my lst blaze rose. The one cane looks like a disaster area but is recovering and then on the second cane I was so thrilled to see it had 4 or 5 buds on it!!! I guess it didn't want to get left out on the fun when it saw the newest blaze rose getting not only buds on it but beautiful red blooms and across from it my coral dawn with 5 or 6 buds on it. So happy for it. Has been thru a lot this year with the winters we have had, then sawfly larvae. Forever getting the robins hopping around in the gardens where the roses are or the song sparrow. Have no bird feeder out the back did have but then the region or the ministry of housing upon seeing it told whoever it was to take it down as it just also attracts other animals to it as we do get rabbits, squirrels and chipmunks. Could just get niger seed or distlefink. Goldfinches, purple finches and redpolls go nutty over them. I know I used to have a hanging feeder back at the house hung on our ash tree out the back and the goldfinches would like literally be fighting with one another on who was going to land on the perches :D Never saw any squirrels come to this one. Went after the ones that had the sunflower seeds or the corn in it. (chipmunk would come to that one and that is all he would take from it is the corn kernels :D )

Skr,

I think that just regular good care of your roses is all they would need to recover -- plenty of water, especially. Water-stressed plants suffer more from fungal and insect attacks, as I understand it. Unless your plants have been completely defoliated and are very young and small, I think they're likely to do fine. Mine were quite young and were badly defoliated over and over and yet they kept growing back.

I don't think it's considered a good idea to heavily fertilize plants when they are super stressed out but I'm not knowledgeable enough to say. I give my roses compost as a side/top dressing and I periodically give them some fish hydrolysate, diluted as per direction. You could trim back your plants a bit (if they aren't very small) to try to stimulate growth. Unless you have plenty of leaves, try not to strip off all the chewed leaves, as even if they look like Swiss cheese, they are still supporting the plant, which needs them.

I've found that as my plants have grown and matured, they are less vulnerable to the rose slug's damage -- they have lots more leaves, and stronger ones, and they can afford to lose a greater number than when the roses were babies.

Other than that, try to keep up with the rose slugs with squishing and/or the Cornell spray, and be a bit patient. I think you'll seem leaf out again before long. Be sure to spray following the safe guidelines -- don't spray while windy and don't spray when the bees are around. Early evening is usually the best time, in my experience. Also, the rose slugs here return several times over the summer months, so -- keep an eye out for their return and try to use the spray before they really move in. I found it was only a matter of a couple of days between spotting a couple of slugs on a few damaged leaves and near-total defoliation.

Good luck.