
The curling under of leaves can be caused my the Sawfly whom injects a substance into the leaves after laying her eggs that makes them curl to protect the eggs. It can also be cause by other egg laying insects. The best way to get at them is by use of a systemic insecticide. I recommend using some Bayer Tree and Shrub Granules applied per the label instructions for Ornamentals/Shrubs/Roses. I have had great success with this product. I use Green Cure fungicide which is a earth friendly fungicide and spray either early morning or early evening once the temps have cooled a bit. Remember to water your rosebushes well the day prior to any pesticide application or even fertilizing them. A well hydrated rosebush is far less likely to have any sort of negative reaction.