Beetles move from flower to flower, consuming the petals before they eat the leaves. They seem to be attracted to light-colored blooms. Pick beetles off plants by hand and destroy them. Spray the plants with an insecticide. In late summer and in spring, treat the ground around affected roses with a grub-controlling insecticide or with milky spore.
Leaves become dry and have a full bronze sheen.
Tiny specks may be visible on the undersides of the leaves. Eventually, thin webbing appears on the foliage. Spider mites, nearly microscopic pests that may be red, black, yellow or green. Mites proliferate in hot, dry weather. Knock adults off plants with a strong stream of water.