What Insect Eats Roses?

At least 10 insect pests attack roses. The Texas A&M University Extension Service says they are divided into two general groups: sucking insects that insert their mouthparts into leaves, buds, stems and canes to suck out the plants' vital juices, and chewing insects that eat plant tissue from leaves, stems, flowers, buds and roots.

Among the most damaging sucking insect pests are aphids and spider mites. Aphids are tiny -- about 1/8 inch -- yellow-green soft-bodied sucking insects that live in groups underneath leaves or on buds or growing tips. Aphids reproduce weekly, so populations can explode quickly. Spider mites are another major rose pest. They are less than half the size of aphids, resemble mini-spiders and come in red, yellow and green shades. They prefer the underside of leaves, where they suck the sap from the leaf veins. Like aphids, spider mites reproduce weekly so populations can grow fast.

Whiteflies and rose midges are tiny, white, soft-bodied flies. The winged adults look like tiny snowflakes as they flutter around plants. Whitefly adults and larvae both suck the sap from the underside of leaves. Rose midge larvae suck out juices from buds and blooms. Rose scale insects are another pest. Adults form a hard light-gray scaly shell on stems. They attach themselves to tender shoots when young and stay there for life, sucking plant juices. Heavily infested stems and canes may become totally encrusted with ugly scales.

Chewing insect pests include several species of leaf-eating and bloom-eating beetles, such as brown June bugs, brown rose chafers, brown Fuller rose weevils, green/bronze Japanese beetles, green rose-leaf beetles and spotted yellow cucumber beetles. Thrips are very tiny golden-yellow winged insects that feed mainly on buds and blooms. Several different moth caterpillars feed on rose leaves, including leafrollers, leaf tiers and raspberry horntails. Other chewing rose pests include grasshoppers and leaf-cutter bees. Roots, stems and leaves can be chewed up by white grubs, snails and slugs.

Signs that your roses are infested with pests include wilting of parts or all of a plant; holes or dark spots on leaves or petals; severed stems, blooms or leaves; malformed blooms or leaves; and a shiny sticky substance called honeydew excreted by aphids and whiteflies that breeds a damaging black sooty mold. The University of Illinois Extension Service says infestations can be minimized by selecting pest-resistant varieties and keeping them healthy with proper site selection, good soil preparation, correct spacing and vigilant maintenance. Natural pest controls include spraying high pressure water from a garden hose to knock bugs off your plants, hand-picking beetles, applying soap sprays and encouraging natural enemies of pests. Severe infestations can be controlled with insecticides such as malathion, orthene or dicofol.