Part of this intensive management is the frequent application of pesticides. However, while insects and mites may attack roses from time to time, many rose enthusiasts are able to maintain vigorous plants and produce high quality blooms with little or no use of insecticides, especially in California's dry interior valleys. The key is careful selection of varieties, which vary significantly in susceptibility to insect and disease problems, good attention to appropriate cultural practices, and occasional handpicking or using water to spray away pests. Keep an eye out for rising populations of natural enemies that often rapidly reduce the numbers of aphids, mites, and other pests.
Aphids are the most common insect pests on roses.
Aphids favor rapidly growing tissue such as buds and shoots. Low to moderate levels of aphids do little damage to plants, although many gardeners are concerned with their very presence. Moderate to high populations can secrete copious amounts of honeydew, resulting in the growth of sooty mold, which blackens leaves. Very high numbers may kill buds or reduce flower size. Keep ants out of bushes with sticky barriers or traps to improve biological control.