Insect Control On Roses
I only use pesticides when there are insects present. (Always follow direction on the product label before mixing or applying insecticides). Most insects can be controlled with pesticides, however, certain insects such as spider mites will require a miticide.
If you have identified spider mites they will need to be sprayed in stages. The first treatment will kill the adults, and the second kills the hatchlings. For a general insecticide I use Orthene but for spider mites I use Avid along with a modifying biochemical (sex attractant pheromone), called Stirrup-M. I also add a product called Indicate to my water to create the optimal pH 6.0 - 6.5 in your water along with a sticker to help it adhere to the leaves better.
Malathion, Liquid Sevin (Carbyrl) and Neem oil are cheaper alternatives that when used properly are quite effective for insect control. Neem oil not only controls many insects and mites but fungus as well. I use Merit for Japanese beetles; it is one of the best. Liquid Sevin also works well for Japanese Beetles. For best results in controlling these pesty beetles you must coat the top and bottom of the leaves.
When winter has arrived, and after we have had a few hard freezes (28 degrees or so), cut back long canes that extend beyond the rest of the bush to make the plant even. Then tie twine around the remaining canes to hold the plant gently together. (Do not cut the bush back completely at this time.) Late February or early March is the best time to do the heavy pruning.
Clean the ground of all leaves and cover the bud union with compost or mulch, to help it through the winter.
When the plant goes dormant, usually around mid-December, spray your roses with a dormant rose spray. I spray with Volck Oil and Lime Sulfur dormant disease spray. It should be sprayed on the ground under and around the rose bush as well. A second spray of Volck Oil and Lime Sulfur in late January or early February can be of great benefit in controlling such insects as scale, and some of the fungi that plague certain types of roses, particularly hybrid teas.