Q.Sawfly eating roses
We’ve just purchased a home with what were probably beautiful climbing rose bushes. It appears that the bushes are being destroyed by what my local garden center identified as sawfly or rose slugs. The roses look horrible and I am wondering if they are too far gone to save and what to do with the carnage that remains? Do I cut it all back and hope for better next year? Rip it out and replace? I have uploaded an image I took about two weeks ago and they look much worse now. We settled in the home for at least a month but I will have access to the property.
I would spray all of them with some Bayer Advanced Complete Insect killer ASAP, then give them all a treatment of Bayer Tree & Shrub Granules per the label instructions and water well. Then in about 4 days water them with some water that has both a root stimulator and a product called Super Thrive in it. Water them with this same water mix a couple times after the first time as well. There is still hope as long as you have green canes. Prune the back only to remove dead or badly wilted foliage.