Eudryas grata, and E. unio.—The Beautiful Wood-nymph, and the Pearl Wood-nymph.—The worms are very much alike, and resemble the Spotted Forrester. The moths come forth in July; the fore-wings are milk white, bordered behind and on the outer side, from the base to the middle, with rusty brown, edged on the inner side with greenish olive; hind-wings nankeen yellow, with a blackish-brown border. These worms are best removed by hand-picking.
Datana ministra, or the Hand-maid Moth.—The moths are troublesome visitors to the evening student in June; they are brown, hairy, thick-bodied, and measure rather more than an inch across the wings. This creature is destined to give us a great deal of trouble by her progeny, for she deposits her numerous eggs on the under side of the leaf on a twig of quince, apple, and cherry trees, where they hatch into worms, that, during their existence of about four weeks, consume immense quantities of foliage, often stripping the trees bare.
The worms feed gregariously, lying side by side in solid phalanx. They are of a dark brown in their younger state, but become lighter and more clearly marked at each successive moulting, so that they are distinctly striped with black and yellow. The peculiar character of this worm is, that when at rest, the head and tail are carried up in the air, or recurved over the body, which is supported by the six prop legs placed near the middle. When disturbed, these caterpillars often throw their heads from side to side, as though in anger. They are sparingly furnished with hairs, and they spin but little; though when young, the worms will sometimes drop from the leaves when disturbed, and hang suspended by a fine strand of silk. At full size, these creatures are an inch and three-quarters to two inches long, and as thick as a goose quill, so that we can readily imagine the amount of destruction which may be committed by one of these armies or family groups of one to two hundred worms.
Treatment.—Constant vigilance is required on the part of the orchardist, and unremitting efforts while the insect is in the larval condition. Fortunately for us, their habits are such as to aid us in a remarkable way. They may be looked for in July, but they become numerous only about the end of August, and in September. Some late broods may be seen on the access of early frosts, but by the end of September, the worms generally perfect their growth, and descend into the earth to undergo their changes for the next season, when the moths will again appear.
When we may be inspecting our orchards, in the summer and autumn, we should observe any defective foliage, as this is often an indication of the inroads of insects. If our trees have been neglected, we may be alarmed by observing some of the thriftiest shoots and branches quite stripped of their leaves; and, lying along the stems, or crowded together, we shall see these unpleasant worms, unless they be foraging upon an adjoining, or sometimes upon quite a distant branch; for, in changing their pasture, they descend one twig and pass out upon another, which may diverge considerably from the first.
In the early stages of their existence, however, the little worms consume only the upper surface of the leaves, and it is at this period that we may most advantageously attack them. The leaves that have thus had their substance eroded become dry and whitish, and attract our attention. They are generally found upon a single twig or spray, usually a lateral, and it should at once be examined, as we may now easily destroy the whole brood by rolling a single leaf between the thumb and finger.
NOCTUÆ, OR OWLET-MOTHS, CUT-WORMS.
The perfect insects are thick-bodied, and of dull colors; they fly at night. The caterpillars are naked, live in the soil, and feed above ground at night, when they do considerable damage. The common Cut-worm, Agrotis, is an illustration. There are several sorts, which have received different names, but the worms all have very similar habits.
The moths are supposed to lay their eggs in July, when they soon hatch and feed during the season; they attain considerable size and hybernate in the soil.
Remedies.—Fall and winter plowing has been recommended, as it exposes the worms to the birds, and to the weather, but especially because it destroys the vegetation upon which they might subsist in the early spring. The only safe way, is to watch their traces among our plants, and dig down beside them, find the worm, and destroy it. Though this does not restore the plant already killed, we prevent further damage, and may hope to thus diminish the pest in future years, which is no small matter. A knowledge of their nocturnal habits has induced some gardeners to go among their young plants with a lamp or candle at night, when they may find the caterpillars feeding. A few choice plants may be protected by wrapping their stems with a strip of paper, or a stout leaf, (hickory), at the time of transplanting into infested grounds; this will save them. Tobacco water has been found very effective, applied to the plants, which it does not injure.