Mealy Bug
(Coccus adonidum). This well-known insect pest to cultivated plants belongs to the order Homoptera, and is very nearly allied to the equally hurtful Scale insects, and the Aphides, or Greenflies. From the latter class it differs in its broader and more flattened form, in having two filaments at the end of the abdomen, in never having honey-tubes, and in the males having only two wings. Scale and Mealy Bug are really group names, that include several kinds under each; and, together, they form the family Coccidae, the males of which are minute, and of the structure described above, having no beak with which to feed. The females are usually very much larger than the males, are wingless, and have a beak. In the Scale insects, the female, after a time, becomes quite inert, and dies, attached to some branch, and covered over with a shield-like coat on the back. In the Mealy Bug, the female remains able to move during life; and her body is covered, not with a shield-like skin, but with cottony tufts of a white substance, the rings of the body remaining quite distinct when the coating is removed. The substance is secreted in the form of a sticky fluid, which, on the death of the insect, assumes the cottony appearance. With this substance the female covers up her eggs.
A number of kinds of Coccus have been described; but the commonest and most injurious in glass houses is C. adonidum. This insect attacks almost all greenhouse and stove plants, Vines, &c., but is partial to Dracaena and its allies, asclepiads, and the members of certain other orders. The male is small, of a pale red colour, covered with a white bloom. It has white wings, the front margin of which is spotted with red; the tail filaments are white, and the antennae moderately long. The female is oblong, wingless, red, but covered with white powder, and has the antennae shorter than in the male. She can move freely till the time of laying her eggs has arrived, when her body remains, as a shield for her eggs, under the cottony substance previously referred to.
Numerous remedies against Mealy Bug have been proposed. Probably, the best are washing and scrubbing the branches and diseased leaves with a wash containing soft soap or infusion of tobacco. Spirits of wine (35 p.c.), applied with a small brush, is said to destroy the insects without injuring the plants. Gishurst's Compound, oils, and Vine dressings, have also been recommended as applications to woody parts, such as branches. All of these are useful insecticides, but are liable to injure the green parts of plants. Smoking, as practised for Aphides, does not materially injure the Mealy Bug's eggs, so that it should be repeated in a few days. Where a greenhouse is much infested, it should be thoroughly cleaned out, and all but the more choice plants should be destroyed. See also Insecticides.