By September, the spray interval should be shortened to every 7 days since disease is more prevalent. Feeding with a water soluble fertilizer should occur every two weeks. Follow instructions by mixing one tablespoon of water soluble fertilizer per gallon of water and pour a gallon of solution around each plant Don't feed with either liquid or dry fertilizers after October 15th so that growth can slow and harden for the winter cold. I have weird looking leaves on the growing tips of my rose bushes. You have a BIG problem but a common one.
Pest control is one of the major problems facing area rose growers.
Insects such as thrips damage flower buds and cause them not to open or to form odd-shaped blooms. These insects must be prevented rather than waiting until damage occurs before acting. Once damaged, blooms are not salvageable. The most notorious of the rose foliage diseases are black spot and powdery mildew, which can severely damage most of leaves and impair the plant's ability to produce a bounty of large, beautiful blooms. Apply Orthene, diazinon or malathion for insect control when necessary.