There are a number of insects and other pests which can damage camellias, but only a few are of great importance. Many growers fail to recognize the symptoms of insect damage before serious injury occurs. To prevent major problems, examine plants regularly for symptoms of these pests.
About 90 per cent of insect problems on camellias are caused by scales. They can go unnoticed until after a large population has developed and considerable damage has been done. They suck vital juices from the plant, and several generations of them can develop in a year.
Tea Scale: This is the most common and probably the most damaging insect pest of camellias. Tea scale infests only the underside of a leaf. Male insects appear whitish, while the females are dark brown. Symptoms include yellow chlorotic splotches on the upper leaf surface. A white, woolly-like, cottony-looking mass secreted by the males may show on the under surface of leaves.
Camellia Scale: Like the tea scale, this scale infests only the leaves of camellia plants. The female is light to medium brown and oyster shell-shaped about 1/10 inch long. The male is similar but shorter.
Peony Scale: This scale is less common than tea or camellia scale; however, when present it is a serious pest. Infestations may kill branches and entire plants if not controlled. Peony scale is found on the stems and branches of camellias and azaleas. They are hard to recognize, as they camouflage themselves well. The hard shell which covers their body is blended to match the color of the stems. If the shell is removed, a white, circular waxy spot is left on the stem.
Wax Scale: This scale is also found on the stems and trunks of camellias and many other woody ornamentals. The waxy covering is white or slightly pink, oval, and 1/4 inch in diameter.
Control of Scale: To control scale infestations, spray plants at the first sign of scale. Oil emulsion sprays, a contact insecticide, will give effective control if applied properly. For it to be effective, the plants must be thoroughly covered. Oil emulsion sprays should be applied only during the spring and fall when the temperature is 40 -85°F. Spraying in the heat of the day can result in burning the leaves. As a general rule, apply no more than three times per year with at least 60 days in between sprays. Oils are compatible with other insecticides.
Aphids or Plant Lice
These pests can become a problem during the peak growing time. They are small insects that form colonies on the undersides of leaves or along the stems of tender new growth. They are rarely seen on mature, hardened tissue. They injure plants by sucking their juices with a long beak. Aphids excrete honeydew, a sticky substance which attracts sooty mold. Aphids are relatively easy to kill using a soap spray, although repeated sprays may be necessary.
Mites are very small, sucking pests that are generally found on the underside of plant foliage. They are difficult to see with the naked eye without using a magnifying glass. Symptoms include a dusty, gray appearance of the foliage. In heavy infestations you may see webs covering infested areas. Heavy infestation may cause defoliation. A single spray of a commercial miticide in mid-May usually prevents severe injury. A second spray applied 10 - 14 days later may be necessary to kill mites which have hatched from eggs. Mites are more severe in a hot, dry climate.
Camellia bud mites are small pests that occur under the layers of vegetative and flower buds. Flower buds with heavy infestations show brown edges on the bud layers early. If left unchecked the buds turn brown and drop before blooming. Thorough spray control is essential to obtain good control of these mites.
For more information on insect and pests, visit the American Camellia Society website.