Beetles in Rose Bushes

The Japanese beetle (Popillia japonica), rose chafer (Macrodactylus subspinosus) and Asiatic garden beetle (Maladera castanea) regularly damage and infest rose bushes in the spring and early summer months. The damage occurs predominately on the foliage, new growth and flower buds.

Identification

• Asiatic garden beetles and Japanese beetles look similar. Both measure approximately 1/2 an inch and are brownish in appearance, but the Japanese beetle has a greenish metallic sheen. Asiatic beetles do not congregate in large numbers on the bush; they feed predominately at night, unlike the Japanese beetles, according to the University of New Hampshire. The rose chafer measures 3/4 of an inch, with a tan topside and a black underbelly.

Effects

• The Japanese beetles cause round holes and chewing along the edges of the rose's foliage. The rose chafer causes widespread damage through feeding on the foliage, new growth and buds. The affected parts die quickly, or buds fail to open. The Asiatic beetle chews the edges of the rose's leaves, but does not do widespread damage to the bush or the foliage itself.

Prevention/Solution

• Handpick the beetles from the plant and drop them in a pan of soapy water. Pick Asiatic beetles at night, using a flashlight, when the beetles emerge from the soil to feed on the foliage. Spray the plants with an approved pesticide only if infestation is severe.