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means may be found for spreading the disease among cutworms, and thus kill them by the wholesale.
Wireworms, the larvae of the "Click beetle" or "Snapping bug" (Elaterida), sometimes bore into the stalks of the plants, but they never attack the leaves.
The "Bud Worm" (Heliothis armigera), Fig. 63, attacks the bud and tender leaves at the top of the tobacco plant before they are unfolded, and sometimes work the greatest injury. One of these worms may ruin a dozen young leaves in a few days. Hand picking is the only remedy for tobacco, though carefully spraying with Paris green is suggested. These worms are always most destructive in cloudy weather. This is the dreadful bollworm of the cotton planter and corn worm of the North. The tobacco bud worm has been observed on weeds belonging to the same family as tobacco, but has not been generally accounted a tobacco insect. At the Kentucky station, worms left tobacco and went into the ground August 10, and adult moths came out August 24 and 25. Since their original food plant was probably some one of the weeds known as ground cherry and horse nettle, it would be well always to destroy such plants when growing about tobacco.
Crickets.—There is a greenish tree cricket ((Ecanthus niveus), Fig. 63, that occasionally does much injury to the leaves of tobacco, by eating round holes in them. It does not kill the leaf or arrest the growth, but the small holes increase in size longitudinally, as the leaves grow in length. This insect begins its depredations in July in the southern tobacco regions, and in August in Pennsylvania. Tobacco planted near trees suffers most from its depredations. This pest infests blackberry and raspberry canes, and tobacco should not be set near them.
Grasshoppers.—The meadow grasshopper (Orchelimum vulgare) is sometimes very destructive on the tobacco plants when first set out, and before they have become established in the ground. One part of Paris green mixed with twenty parts of wheat flour and a smart quantity dusted on the plants while the dew is on them, will destroy these pests. Frequent workings of the land will also drive them from the field. All weeds and other unnecessary growth likely to harbor these pests during the early part of the season, should be destroyed as a precaution against late summer injury.
Several species of grasshoppers are likely to be so starved for forage that in July or early in August they are often forced to attack tobacco, but in Kentucky the greater part of the holes gnawed in leaves (Fig. 64) is the work of the red-legged grasshopper, shown in Fig. 65.
To kill the grasshoppers, the mixture of Paris green above mentioned is put in a bag made of thin cloth, which is tied to the end of a pole four or five feet long. Walking between the rows when the dew is on the plants, the bag is held over each and a slight tap given to the stick. A portion of the mixture falls upon each plant, and adheres to the surface of the leaves. This application is said to destroy the grasshoppers completely. Too much of this mixture should not be put on a plant, not enough to make it whitish.
Sucking Bugs.—In Pennsylvania, and other seedleaf growing districts of the North, there is a class of hemipterous insects that puncture the leaves of the tobacco plant and suck out the juices. One of these is a small, gray insect or bug, about a quarter of an inch long, known among entomologists as Phytocoris linearis. In Tennessee, and other southern States, this species feeds upon the parsnip, the tomato and the cabbage plant, but rarely on the tobacco plant. A larger insect, belonging to the family Scutelleridce, known as the Euschistus puncticeps, preys upon mullens, thistles and other weeds as well as upon the tobacco plant, but its injuries do not seem to be so decided as the first named. These bugs make very small holes in the leaf, but the damage resulting from them is inconsiderable.
The Tobacco Miner is a new pest that attacked tobacco for the first time in 1896, being noticed in three townships in one county in North Carolina. The caterpillar is about half an inch long, and greenish, with a dark brown head. It makes an irregular or blotch mine by eating the green matter between the two sides of the leaf, leaving the skins intact and the leaf transparent. The caterpillar is extremely voracious and as several usually mine one leaf, the leaf is soon rendered worthless, and it is feared that the pest may be widely prevalent. It has been carefully studied by Gerald McCarthy, botanist North Carolina experiment station, and the facts and illustrations (Fig. 66) are from its bulletin 133.
The insect is a native whose common food plant has been the perennial weed, Solanum Carolinense, commonly called horse or bull nettle. This weed is rather common on dry, sandy soil from Connecticut southward along the coast to Florida, and westward to the Mississippi. The range of the insect is co-extensive with its host plant, and includes nearly the entire tobacco-growing area of the United States. It is well known to economic entomologists that the natural increase of any insect is chiefly regulated by the abundance of its food plants. Insects which subsist upon a few species of weeds of waste ground must necessarily lead a very precarious existence, and do well if they hold their number from year to year. When such an insect changes its wild food plant for a cultivated species, the relatively almost infinite abundance of the latter causes a parallel increase of the insect, which, soon overflowing its natural boundaries, or the range it occupied before, spreads into all regions where the new host plant is cultivated. This has been the history of the Colorado potato beetle, which originally subsisted upon another solanaceous weed.
Description of the Tobacco Miner.—Gelechia picipellis, Zett. General color, yellowish gray. Head and thorax paler than wings, inclining to cream color. Palpi simple, not exceeding the vertex. Primaries variegated, with a few smoky streaks and a marginal row of minute black spots at base of cilia. Wing expanse 0.45 to 0.50 inch. Length 0.20 inch. (After Miss M. Murtfeldt, 1881.) The insect belongs to the natural order Lepidoptera, sub-order of moths. Family
of Teneids, of which the more important are the clothes and fur moths, and the Angoumois grain moth or "Fly weevil" [Gelechia—Sitotroga—cerealella), so destructive to corn and grains in the crib. The latter species is very closely related to and greatly resembles our tobacco miner.
Remedies.— None have been tried as yet. From the nature of the case, the treatment must be preventive. The parent moth deposits her eggs within the substance of the leaf or stem of the plant. The resulting caterpillar eats the green matter of the leaf, leaving both epidermes intact. These surfaces, in the case of tobacco, are oily and will readily shed any liquid, and they also prevent any powder from penetrating or touching the insect within. It is within these mines that the caterpillar appears to pass its whole larval and pupal life, issuing as a winged moth to lay eggs as before. The number of annual generations is yet unknown, but is probably not less than three. The insect is believed to hibernate in the imago or winged state, though it may also lie dormant, either as caterpillar or pupa, hidden in the stumps of tobacco or the roots of the bull nettle. The most promising remedy at present is the extirpation of the bull nettle in all tobacco-growing sections, and the prompt plowing under or removal of tobacco stumps as soon as the crop has been gathered. Watch for leaves showing the miner's transparent blotches, and when found, remove and burn them.
The Tobacco Worm.—This is the great arch enemy of the tobacco plant and absolutely sets a limit to the culture of tobacco. It reduces the acreage fully onehalf. But for its destructive power six acres might easily be cared for by one man. There is no remedy for them, but to search every leaf and destroy them. The worming of the crop, when they are numerous, is the most disagreeable and tedious work attending tobacco growing. Some seasons there are comparatively few, again, they seem to infest every leaf. Worming has been done so persistently in many places in the Connecticut valley that this pest is well-nigh exterminated. But under more careless methods at the South, immense injury is done by the tobacco worm, as may be inferred from the photograph in Fig. 67, of an entire crop utterly destroyed by this pest. Fields of tobacco that give promise of making the finest wrappers may be totally ruined for that purpose through a week's neglect in catching the worms. It matters but little how rich the soil may be, or how well cultivated, the crop will be a total failure unless these worms are destroyed. So important