Woolly Aphis
(Schizoneura lanigera). An insect more often called the American Blight. A few particulars may be added to the account already given of this very dangerous pest to Apple-trees. The wingless females are oval and flattened, with deep constrictions between the body-rings. In general appearance they much resemble blackish-brown Aphides; but the antennae and limbs are very short, the tail is very small, and the two honey-tubes are extremely small. These wingless females live on the bark, sucking its jucies, and produce multitudes of living larvae, like themselves on a smaller scale. In autumn, winged viviparous females also are found, differing from the wingless females in little but the possession of wings. The winged females produce small, ill-developed insects, of which each gives birth to one egg for the continuance of the species during winter. The larvae seem to suffer very little from the action of low temperatures, as they are protected under the cottony excretions with which they cover themselves. It is said that in winter they fix themselves on the roots of Apple-trees, and such the sap from them, returning to the branches in spring. The pupae are like the winged females, except in having the wings represented only by little scales. The males are small, and, like the winged females, are unable to suck, as the beak is undeveloped.
The popular name (American Blight) points to the belief that this insect has been imported from America into Europe. The earliest European record of its occurrence dates from 1787. In England, it was first observed in a nursery, near London, in which were Apple-trees recently imported from North America. It soon spread, with disastrous results, into the orchards of Devonshire. In Germany it was first observed in 1801, in France and Belgium in 1812. It is now plentiful in many parts of Europe. It feeds on the wild Crab Apple of North American; but several leading American entomologists believe that it has been carried from Europe to America, and not in the reverse direction, as generally supposed.
Remedies. A number of the more highly recommended remedies are mentioned under American Blight. The most important point to attend to is the thorough cleansing of the branches, by the aid of a thick brush and any good insecticide, e. g., soft soap in water, alone or mixed with crude carbolic acid of such a strength that the acid does not separate as oily drops when the soap is mixed with water. Usually, about one part of acid to ten of soap is sufficient, thoroughly mixed before water is added. The solution may be used moderately strong to the older branches, weaker to the younger ones. Kerosene may be used instead of the above--Professor Comstock states that he has sprayed it pure on plants, without injury to them--but it is usually employed diluted with four or five times its bulk of water; in this strength it may be applied to the branches without risk of injury. Another useful remedy is employed thus: Towards the end of autumn, or in winter when the weather is mild, the earth for about 3ft. from the tree is thrown back from the old roots, and one or two pailfuls of lime-water, or of lye of wood ashes, is poured in; then about 1in. of newly-slaked lime is scattered in, and the earth is replaced. All small branches on which the insect is established should be cut off and burned.