Rose beetles
Rose beetles, also known as rose chafer or rose bug are yellowish brown in color and about a half-inch in length. Sometimes a dozen or more will be found clustered upon a single bloom, which will be completely demolished. Rose beetles are the most destructive of our rose pests. They appear in hordes just as the first roses are coming into bloom, and their destruction continues through the height of rose season. Seldom are they seen in subdivisions of suburban areas, as conditions are not favorable for them because the land is closely cultivated. In open areas, where open fields are common, conditions are ideal for them. Here they multiply in vast numbers. They are not apt to be so numerous in areas of heavy clay because it is almost impossible for the females to deposit their eggs.
Adult rose beetles appear in early June and feed for about six weeks. Toward the end of this period, females deposit their eggs. Females select a rough, grassy place where soil is somewhat sandy. They bore into the ground for a depth of 3 to 6 inches, and lay their eggs singly in tiny soil pockets. The white oval eggs hatch in about two weeks. The larvae feed on decaying vegetable matter and upon the roots of weeds and grasses. Maturity is reached in late October. Then they burrow down into the soil about 12 inches, and curl themselves into little earthen cells for the winter. In the spring, the grubs work their way up toward the surface again and usually feed for a short time before they pupate. The pupa stage varies from three to four weeks. The adult beetles emerge just as the first roses are coming into bloom.
As a means of protection against rose beetles where infestations are severe, rose beds may be temporarily covered with mosquito netting or a cheap grade of tobacco cloth tacked onto a light frame.