Adult -The adult rose chafer is a tan, slender beetle with a reddish head and long, spiny, reddish legs (8 to 13 mm in length). The female is somewhat more robust than the male. The wings do not quite cover the abdomen.
Egg -The oval, shiny, white egg is 1 to 2 mm long.
Larva -The larva resembles a white grub (May beetle larva) but is smaller (up to 18 mm in length) and more slender.
Pupa -The light yellow-brown pupa is 16 mm long and has the last larval skin clinging to the posterior. .
Host Plants -Rose chafers seem to prefer the flowers of roses and peonies, new grapes, and leaves of grapes. They will feed on apple, cherry, dahlia, elder, elm, foxglove, geranium, hollyhock, hydrangea, pear, poppy, Virginia creeper, and wisteria. The grubs feed on the roots of turf, weeds, and nursery stock.
Damage -Rose chafers are remarkable for the variety of hosts upon which they feed and because they are poisonous to chickens and birds when eaten. Rose chafers consume petals of roses and other flowers. The foliage of various broadleaved plants is skeletonized. Rose chafer grubs feed on the roots of grasses, weeds, and nursery stock.
Life History -Rose chafers appear in late May or early June and feed on roses, peonies, and sometimes iris and other flowers. They also feed on grapes and at times may damage elms, birches, and other trees severely. The adults live for about 4 to 6 weeks. Eggs are laid about 15 cm deep in sandy or grassland soil, and they hatch in 1 to 3 weeks. The eggs are laid in groups of 6 to 40, but each egg is deposited in a separate cavity. The larvae feed on the roots of turf and ornamental plants. They apparently move down into the soil for moisture. The larvae spend the winter deep in the soil. In early spring the grubs migrate upward and pupate in early May in earthen cells. There is one generation per year.
Prize rosebushes may be protected by a cheesecloth frame while the beetles are in flight (most of June). Handpicking the beetles may help. Rose chafers should not be fed to poultry or family pets; these insects are poisonous (apparently because they contain cantharidin, a blistering agent). For specific chemical controls, see the current state extension service recommendations.
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