Scientists tell us that more than 40 species of scale insects feed on some part of the camellia plant.
Fortunately, few of these will be encountered by the average camellia grower, but as with any pest, these few may prove very disastrous.
Scales may quickly rob a plant of its vitality and render it incapable of making proper growth and producing any bloom; before you realize what is happening, they may even kill the plants completely.
They do not eat the plant tissues but feed by drawing out the vital juices from bark, bloom, leaves, or stems.
Following are a few of the most important scale insects.
Tea Scale
Tea scale is by far the most damaging one that attacks camellias in the South. It is also important in some Pacific Coast areas.
It attacks the leaves only and always on the undersides except in dense, crowded growth cases.
Yellow splotches show heavy infestation on the upper surfaces of the leaves. The severity of the infestation determines the size of the splotches. The undersides of the leaves will have a whitish, cottony mass.
The breeding season is long, but the heaviest showing of crawlers, as the young are called, is in March and September.
At maturity, they are about 1 /20th of an inch long; the females are brown, and the males are almost white.
Camellia Scale
The Camellia scale is less important than the tea scale but causes much damage in some areas.
Unlike the tea scale, this scale feeds on the leaves but does not discolor them. It is about 1/10th of an inch long, shaped somewhat like an oyster shell, and dark brown.
The heaviest breeding seasons are in March and September.
Peony Scale
The peony scale seems to be increasing in importance in the Deep South. However, unlike the two scales previously mentioned, this one mainly attacks the woody parts rather than the leaves, resulting in dead and dying twigs found on badly-infested plants.
Light spots are left on the bark after the adults die and drop off.
These scales are circular, about 1/10th of an inch in diameter, and dark in color—very nearly the color of the bark of the plants.
In most areas, only one generation is produced annually, usually in early June.
Camphor Scale
Camphor scale, like the peony scale, attacks the wood, although the males may attack the leaves in cases of heavily infested plants.
They are up to 1/10 of an inch in diameter and yellowish brown. In June and September, the crawlers are usually most in evidence.
Florida Red Scale
Florida red scale makes its heaviest infestation along the hot, humid areas of the Gulf Coast and is not generally found more than a hundred miles or so inland.
The females are 1/12 of an inch across, circular in shape, and dark brown to almost black. Both young stems and young leaves are attacked.
Chaff Scale
Chaff scale is more troublesome on the Pacific Coast than in the South. It is about 1/15th of an inch in length and is dark brown.
Some of the Ligustrum (privets) appear to be hosts for this insect.
Soft Brown Scale
The soft brown scale is about 1/10 of an inch long and 1/16 of an inch in width and, as the name indicates, is brown.
It attacks new growths, both leaves and stems.
Oil Emulsions in Handling Scale
Florida Volck and similar oil emulsions are quite effective in handling scale insects and have been standard for several years. The newer sprays containing malathion have also been found effective.
Oil sprays should not be applied when the temperature is above 85° degrees Fahrenheit, but malathion may be applied anytime.
I have found materials containing malathion effective when applied during the breeding season of the various scales.
Since mature scales have a hard protective armor, an insecticide should be applied to be most effective before the hard covering develops.
Experienced gardeners consider the timeliness of sprays of equal importance to the material used. So be sure to get the spray on when the insects are still young.
If Your Plants Are Free of Scale
Two applications annually, one in March and another in September, should keep them clean, but plants badly infested with tea or camellia scale should have two sprayings, two weeks apart in both spring and fall.
Most scales are hatched from eggs laid under the mother’s protective shell. The young soon hatch, crawl out, find a suitable location, and attach themselves to some part of the plant for life.
They are not gypsies. In the case of the soft brown scale, the young are born alive. Scientists say no males have been found.
Due to the seriousness of scale infestation and the importance of keeping your plants clean, all camellias should be carefully checked at least twice each year.
Look for the telltale yellow splotches on top of the leaves and the insects on the undersides.
44659 by Ben Arthur Davis