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It’s Been A Good Fall For Scale Insects

scale insects

Cottony-cushion scale insects are currently a common site in the area. Populations are highest in the drier months of fall and winter, and this has been an especially good fall for this species.

By Les Harrison
Wakulla County Extension Director

With the holiday gift giving season only weeks away, many are scrambling to find the perfect item for those to be on the receiving end.

As the old saying goes, good things come in small packages. Well, most of the time.

There are always gift cards, the 21st Century equivalent of cash, or cold hard cash (one size fits all). Either fits easily in an envelope with an appropriate card, sentimental or humorous.

Of course, there is always the jewelry option. In specific incidents the tiny boxes lead to big expectations.

However, surprises which arrive in small, subtle ways do not always mean a big pleasant surprise.

In the case of Wakulla County’s home horticulture and native plants, the often overlooked and miniature revelation are scale insects.

Scale insects vary dramatically in appearance, but most are very small and frequently escape notice without the aid of a magnifying glass.

Worldwide there are approximately 8,000 species of scale insects found on every continent except Antarctica.

In Florida there are over 180 species of scale insects. The local scale insects are plant parasites which feed on the sap and juices drawn directly from the plant’s vascular system.

There are several family groupings of scale insects. In general they can be divided into two main categories, either armored or soft. Wakulla County and the north Florida have both kinds.

Some are very particular about their choice of host plants, while others are far less selective. All use their hair-like mouthparts much like a soda straw to suck the nutrient laced juices.

Unfortunately some are guilty of more than robbing plants, shrubs and trees of needed fluids.

The piercing action used by this insect creates an opening or wound on the plant’s surface which frequently produces exposure to a variety of diseases.

When scale insects are not controlled by biological or chemical means, the concentrated populations damage leaves, fruit, twigs, branches, and trunks of the host.

Usually scale populations increase slowly over a period of weeks or months on isolated trees or geographic areas favorable to their development.

Some of the native scale insects produce honeydew, an amber residue which attracts ants.

Sooty mold will grow on these deposits and reduce the photosynthetic capability of the leaves.

Female soft scale insects are mobile during initial life stages up until they begin to produce eggs. In their final location, adult females will appear more dome-shaped or produce a cottony elongation on their body, which contains the eggs.

These structures can contain thousands of eggs at a time and enable rapid increases in scale insect populations. Adult males live for only a day or two.

During this terminal stage of life, the scale insects become especially vulnerable to predatory, carnivorous insects. Unable to move, they literally become a stationary target.

Chief among the predating insects is the ladybug or lady beetle. This brightly colored native is in reality a flying, armored eating machine which quickly converts a colony of scale insects into an open air smorgasbord.

While not exactly a small package to the ladybug, scale insects are certainly a good thing to have on their menu.

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