From: https://web.extension.illinois.edu/roses/disease.cfm
Aphids:
Aphids are very common pests. Aphids are soft-bodied insects that can be red, green, yellow, or black. They feed on very young succulent shoots, causing distortion. Aphids are often kept in check by natural predators. Alternative control measures include using insecticidal soaps, strong streams of water to knock them off the plant, or insecticides.
Japanese Beetles:
These hard-shelled, metallic-green, black, and gold insects can cause extensive damage to roses just by their sheer numbers and voracious appetite. They prefer flowers and flower buds but will also attack foliage. Japanese beetles are difficult to control because they are strong fliers and constantly reinvade the area. We recommend using Diatomaceous Earth to help control numbers. Beware of Japanese beetle traps. Do not use traps, as they will draw a great number of beetles into an area, making the problem worse. Hand-picking is also a suggested control for small numbers of beetles.
Leaf Cutter Bees:
It is unusual to see the insects at work, but they make their presence known by the perfectly round holes cut near the edges of the leaves. These leaf pieces are used to make egg partitions inside their burrows. The damage they cause is strictly cosmetic and warrants no control.