. Economic entomology for the farmer and fruit-grower. Beneficial insects. THE INSECT WORLD. plants. Or they may be thoroughly sprayed with the Bordeaux mixture immediately after being set out. Of somewhat larger size and more slender, graceful form are the species of Systena, and of these, S. blajida, the '' pale-striped flea-beetle," has become best known by reason of its injury on a great variety of plants, including sugar-beets. As with the other "fleas" it is injurious in the beetle stage only, and, as a rule, in early summer on young plants. I have seen it ruin an entire f
. Economic entomology for the farmer and fruit-grower. Beneficial insects. THE INSECT WORLD. plants. Or they may be thoroughly sprayed with the Bordeaux mixture immediately after being set out. Of somewhat larger size and more slender, graceful form are the species of Systena, and of these, S. blajida, the '' pale-striped flea-beetle," has become best known by reason of its injury on a great variety of plants, including sugar-beets. As with the other "fleas" it is injurious in the beetle stage only, and, as a rule, in early summer on young plants. I have seen it ruin an entire field of carrots, and have found it on melons, potatoes, beets, and pig-weed in equal abundance. Its life history has not been pub- lished, but its larva is said to feed upon corn-roots. This is cer- tainly not universally true, and its native food-plant in the early stages remains to be ascertained. As with other leaf-feeding forms, we are referred to the arsenites, or, as a means of protection only, to air-slacked lime, which will drive the beetles to wild plants, leaving the lime-dusted crop free. In the genus Phyllotreta we find another series of small species not exceeding one-eighth of an inch in length, ordinarily black in color, with yellow stripes or spots on the wing-covers. The Fig. 221. most common species in the East is the '' wavy-striped flea- beetle," P. vittata, in which there is a distinct yellow stripe through the middle of each ely- tron. The adults feed upon the leaves of cabbage, radish, mus- tard, and others of the cruciferae, while the larvae live as miners in the tissues of the same plants. In dealing with this species the important points are clean culture and keeping down all cruciferous weeds. If in addi- tion all crop remnants are promptly gathered and destroyed, no serious danger need be apprehended. Following the flea-beetles is a series of very curious, somewhat wedge-shaped insects, the Hispidce, in which the antennte are thickened, and the
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