Green Colored Insects on Roses

Aphids

• Rose leaves and stems that look sprinkled with pale-green jimmies have infestations of rose aphids, or Macrosiphum rosae. These insects attack in colonies, sucking fluids from a rose's soft tissues. They seldom move, even when disturbed. The larvae emerge directly on plants from eggs deposited the previous year. Large numbers of aphids rob roses of their vigor, reducing flower size and numbers. Strong blasts of water from a garden hose, repeated as needed, remove small aphid infestations. Introduce ladybugs and lacewings, both of which are aphid predators, into your garden for more eco-friendly aphid control.

Rose Leafhhoppers

• Their habit of scuttling about like crabs when disturbed simplifies the task of identifying green rose leafhoppers, or Edwardsiana rosae. Leafhopper adults measure between 1/4- and 1/2 inch long, with tapering hind ends. Their wingless, translucent white offspring hatch in spring from purple eggs laid beneath rose cane bark the previous autumn. Bacteria infesting breaks in the bark where the larvae exit sometimes cause fatal stem cankers. Both larvae and adults suck fluids from the undersides of a rose's leaves. Large populations can defoliate, or even kill, a rose bush. Control measures include saturating the undersides of infested rose leaves with acephate-, permethrin- or malathion-based insecticide. Imidacloprid soil drenches are effective alternatives.

Japanese Beetles

• Copper-hued wing covers that fold back to reveal iridescent, emerald bodies make Japanese beetles, or Popillia japonica, almost as eye-catching as they are destructive. These 1/2-inch pests overwinter as grubs in the soil. Adult beetles emerge in midspring. They mate and lay eggs while feeding on a rose's foliage, buds and flowers through the summer. Their offspring devour rose roots before burrowing deep underground to avoid winter cold. The larvae attack the roots again in spring before pupating and maturing. Adults leave flowers and leaves ragged or completely decimated. To control the grubs, spray your lawn with a commercial product containing Bacillus popilliae.The larvae-killing bacteria spread through the soil, and protect your roses from homegrown Japanese beetle infestations. You'll still have to watch for invading adults.

Limiting Damage

• Vigilance is the most effective strategy for keeping insects off your roses. Become familiar with the appearance of different pests and the specific symptoms of their presence. Aphids and leafhoppers favor the undersides of rose foliage; Japanese beetles flock to buds and blooms. Checking a rose's vulnerable parts at least weekly enables you to stop infestations in their earliest stages, when damage is minimal.