Scale Insects

Aiton's Encyclopedia (1910)

small, flattened bugs. The females are wingless, and are protected by a scale-like covering produced from a wax of the body which hardens on exposure to the air. In place of a scale, the wax of many species, called mealy bugs, takes the form of grains or powder. Nearly every fruit has its corresponding scale insect. The San Jose scale, the dreaded pest of California fruit growers, is capable of rearing 2,500 adults a season. See article on SPRAYING for means of holding scale insects in check. The orange and lemon growers of California and not infrequently of Florida inclose their trees one by one in a light, gas-tight tent, and fumigate with a poisonous gas. Sprays of whale oil, soap, and crude petroleum are effective. Scale insects cannot fly, but they spread by clinging to young trees from the nursery. In some states all nursery stock is required by law to be fumigated before it is shipped. Scale insects damage fruit to the extent of millions of dollars annually. There is no prospect of their extermination. However, science has won a notable victory over the cottony-cushion scale. This insect was introduced from Australia on nursery stock and soon overran orange and lemon trees to the utter dismay of fruit growers. On investigation it was found that it is held in check in its native home by a lady-bug beetle. A colony of these beetles was turned loose in California and throve wonderfully on the scale insect until the dangerous pest is now practically extinct. The lady-bug no longer having food to live on has gone with it. See San Jose Scale