longer or shorter proboscis of the moth of each. measure about two inches in length.

The pupæ

The Northern species occurs throughout the United States and into Canada. It is also found on Jamestown weed, matrimony vine and ground cherry. The moths appear from May to June, according to locality and season, and as far north as New York City two generations are annually produced. The writer and others have noted two generations in Maryland and Virginia, while as far south as Florida, according to Quaintance, a third generation occurs. The moths deposit their eggs, usually singly, on the under surface of leaves. The eggs, according to Alwood's observations in Virginia, hatch in from four to eight days, and the caterpillars in the course of their growth cast their skins four times in less than a month. When full grown they burrow into the soil and transform to pupa. Both "worms" are sometimes quite dark in color, but when they turn nearly black they are usually infected by a bacterial disease, which invariably kills them (fig. 147).

Fig. 147.-Southern tobacco worm dead and shriveled from bacterial disease. Natural size. (After Howard, U. S. Dept. Agr.)

Few observing persons have failed to see at sometime in their lives the caterpillars of these or other sphinx moths entirely covered with little white oval cocoons. These produce small four-winged parasites, and it is owing to the abundance of these and the bacterial disease that the insects are not more numerous than they are.

REMEDIES. The amount of damage done by tomato worms will vary according to the vigilance of the grower. On small patches the "worms" are readily seen after a little experience,

and can be picked off by hand and destroyed, and if this is carefully done little apprehension may be experienced of damage. Clean culture and crop rotation are always to be practiced and the leaving of tobacco suckers, or abandoned remnants should be avoided, as the "worms" frequently remain in the field until the plants are killed by frost. It should be unnecessary to add that the worms may be killed by spraying with arsenicals. Turkeys are utilized in destroying these insects in the South.

The Southern tobacco worm (Phlegethontius sexta Joh.).— The differences of this species and the preceding have been pointed out. In brief, the moth (fig. 148, a) is darker, and the five orange spots on the body are larger and brighter. The "worm" has only seven oblique white lines on the sides, and

Fig. 148.-Southern tobacco worm. a. Moth; b, full-grown caterpillar; c, pupa. Half natural size. (After Howard, U. S. Dept. Agr.)

the tail is more curved and red. The pupa has a shorter proboscis. The Southern tobacco worm is distributed through the United States from the Atlantic to the Pacific, and from

Canada to the West Indies. No important differences between these two species have been noted as regards habits, time of appearance, susceptibility to diseases and to parasitic attack. In the writer's experience, the two species undergo their transformations throughout in about the same time.

REMEDIES are the same as for the tomato worm proper previously treated.

The Tomato Fruit Worm (Heliothis obsoleta Haw.). This insect, as most modern farmers are aware, is the same species as the bollworm or corn-ear worm. It has been treated from

Fig. 149.-Tomato fruit worm boring in tomato. (After Riley)

the standpoint of a cotton pest in innumerable publications, and is considered among corn insects on page 207, but as yet we have discovered no direct remedy for it in its occurrence on tomato. It is frequently the cause of serious trouble to tomato growers over large areas, due to the "worms" eating into and destroying the green and ripening fruit.

REMEDIES. For the protection of tomatoes, it is advisable not to plant in proximity to corn or cotton fields or on ground that has been grown the previous year to these crops or to beans or cowpeas, all of which are favorite host plants of this pest; nor should land be planted with tomatoes in infested

regions until it has been fall or winter plowed. Although no reports are available of satisfactory experiments having been performed in spraying for this species in its occurrence on tomato, it is possible that a spray of Paris green and Bordeaux mixture, or of either alone, might be satisfactory. It is therefore suggested that three out of four plats of equal size be treated experimentally in each of the manners described, the fourth plat to be left untreated, so that the effects can be noted. Spraying may be practiced up to about a week from the time of the fruit ripening without danger of poisoning human beings.

Miscellaneous Insects. Of insects most to be feared when the plants are first set out are cutworms of various species. The tomato grower is well acquainted with these pests, and no description of their methods is necessary here, beyond the statement that they cut off and destroy more than they eat and resetting is frequently necessary. Cutworms are discussed more fully on pages 49 to 56.

Flea-beetles also attack the plants soon after they are set out. Their injuries can be prevented by dipping the young plants before setting in a solution of arsenate of lead, about 1 pound to 50 gallons of water, or Paris green, I pound to 100 gallons. See page 65 on flea-beetle remedies.

CHAPTER XV

INSECTS INFESTING THE SWEET POTATO

THE Sweet potato is a staple from New Jersey and Maryland southward. It is seldom that plants are not more or less infested by insects, and of these the tortoise beetles are conspicuous because of the holes which they eat in the leaves. As the crop is started under glass and transplanted, it is subject to attack by cutworms and similar insects. There are several other defoliators, blister beetles, the larvæ of sawflies, a hawkmoth and others; flea-beetles sometimes do considerable injury, while in the extreme South the sweet-potato root-borer is becoming an important pest from its destruction of the tubers. In spite, however, of a considerable number of insects which attack this plant, it does not, on the whole, suffer very material injury save in restricted areas and in years when certain pests are abnormally abundant. The root-borer, however, threatens to be a permanent pest in the Gulf region.

The Sweet-potato Root-borer (Cylas formicarius Ol.).-Injury by this insect in North America was first noticed about 1877 near New Orleans, La., when it was claimed to threaten the destruction of the sweet potato crop of the country, a prediction which was, happily, not verified until about 1903.

The adult is a weevil of ant-like form except for the long snout which it possesses (fig. 150, a). It is small, about onefourth of an inch in length, including the snout, the elytra are shining dark blue, the head and snout darker blue, and the thorax and long legs shining red. The larva (b, c) when grown is about one-fourth of an inch long, white, with brown head and darker mouth-parts.