Rose Insect
Pests
Aphids
Aphids are very common pests. Aphids are soft-bodied insects that can be
red, green, yellow, or black. They feed on very young succulent shoots, causing
distortion. Aphids are often kept in check by natural predators. Alternative
control measures include the use of insecticidal soaps, strong streams of water
to knock them off the plant, or insecticides.
Japanese Beetles
These hard-shelled, metallic-green, black, and gold insects can cause
extensive damage to roses just by their sheer numbers and voracious appetite.
They prefer flowers and flower buds but will also attack foliage. Japanese
beetles are difficult to control because they are strong fliers and constantly
reinvade the area. Home gardeners still find that Sevin provides the best
control, but it is only topical. This means that reapplication needs to be done
on a regular basis to protect the foliage and flowers. Beware of Japanese
beetle traps. Traps are almost too effective and will draw a great number of
beetles into an area, making the problem worse. If they are used, they should
be placed in areas away from the rose garden. Hand picking is also a suggested
control for small numbers of beetles.
Leaf Cutter Bees
It is unusual to see the insects at work, but they make their presence known
by the perfectly round holes cut near the edges of the leaves. These leaf
pieces are used to make egg partitions inside their burrows. The damage they
cause is strictly cosmetic and warrants no control.
Spider Mites
Mites are very tiny relatives of spiders. They can be red, black, or brown
in color. Mites pierce the underside of rose leaves and suck sap, causing the
leaf to turn gray or bronze. A fine web is a sign of a heavy infestation. Mites
reproduce rapidly, resulting in high populations in a short time. Mites
flourish in crowded, stagnant gardens. A high-pressure washing with water from
a garden hose directed to the underside of the leaves every 2-3 days can manage
mites. This will interrupt their life cycle. Miticides such as dicofol help in
heavy infestations. Insecticidal soaps are also effective in controlling mites.
Thrips
Thrips are extremely small, brown insects usually living and feeding inside
of the blooms. A deformed flower with flecked or scratched petals is usually a
sign of a thrips problem. The rasping mouth parts of thrips causes this injury
when they scratch the petal surface to feed. Thrips are especially attracted to
yellow or light-colored roses. Some control can be achieved using materials
such as orthene, malathion, or insecticidal soap, but even these often give
poor results. They tend to be worse during late June, July and August when
temperatures are warm.
Rose Midge
The rose midge is a tiny fly that lays eggs in the buds and shoots of roses.
The larvae that develop start feeding and causes bent, mishapen or blasted
flower buds and withering of the stem tips. Eventually they turn black. Control
consists of pruning out buds and applying insecticide if the problem persists.
Midge damage usually shows up in July. Because the larvae fall to the soil to
pupate, an effective control is to place weed barrier fabric under the plants
to catch the larvae and prevent them from entering the soil to pupate.
