The garden geranium, or pelargonium, has more than 200 species and well-known hybrids. These plants have a wide variety of flower colors, growing habits and scents. The leaves are almost completely circular. Geraniums have fragrances that include lemon, orange, pineapple, nutmeg or lime.
Tobacco (Geranium) Budworm
The tobacco budworm has caterpillars that attack the flower buds and reproductive parts of the developing geranium. The injured buds do not open. Failing to produce open flowers is the first outward sign of a problem. Petals of emerged flowers can also be chewed apart. The amount of damage done progresses through the season and becomes the most obvious in summer.
Monitor for early detection of infestation by checking buds and flowers for small holes. With small plants, the most practical control is picking off the caterpillar by hand. The larvae are most active at dusk and easiest to discover at that time. The budworm is not easy to control with insecticides. The most recommended insecticide is pyrethoid, available under a variety of trade names.
Aphids attack a wide range of plants. They are generally on the underside of leaves, buds and new growth. Some signs of aphids are their whitish shed skins and honeydew. Foxglove aphids cause more leaf destruction than some other aphids. Aphids suck plant fluids from the geranium. This causes deformed leaves and makes new growth curl. Consult a garden center or nursery on insecticides for your specific type of aphid.
While they develop, whiteflies can be found on the underside of leaves. They are another bug that uses their piercing mouth parts to remove fluid from plant tissue. A few adult whiteflies on plants can be an annoyance. However, feeding by a large number can weaken or kill a plant. Whiteflies also produce sticky honeydew that aphids and other bugs excrete. Insecticidal soaps can be tried first, but consult a local garden center or nursery for commercial insecticidal information.
Mites also use their piercing-sucking mouth parts to extract plant fluids. They cause injury to geraniums by feeding on the upper leaf surface and giving the characteristic mottled or speckled appearance on the leaves. A large numbers of mites can produce webbing that can completely cover the whole flower. Mites can be easily removed from a leaf surface before they dig in by a weekly hard blast of water. Spray the undersides of the leaves and the lower parts of the plant. Otherwise they can be controlled or treated by spraying oramite at 0.2 pounds per gallon of water.
The best treatment for any bug infestation is prevention before there becomes a problem. Unnoticed bugs and pests can infect other plants, causing damage to entire gardens or collections of houseplants.