Economic entomology for the farmer Economic entomology for the economicentomolo00smit_0 Year: 1896 298 ECONOMIC ENTOMOLOGY. and sometimes three or more broods in the course of the year, and in favorable seasons these become successively more numer- ous, so that the fall brood proves the most troublesome. These favorable seasons, however, do not often occur, particularly in the Eastern United States, and here climatic influences or other natural conditions reach the insects during the winter, so that in the spring following only a normal number survive. Cultivating land in crops w
Economic entomology for the farmer Economic entomology for the economicentomolo00smit_0 Year: 1896 298 ECONOMIC ENTOMOLOGY. and sometimes three or more broods in the course of the year, and in favorable seasons these become successively more numer- ous, so that the fall brood proves the most troublesome. These favorable seasons, however, do not often occur, particularly in the Eastern United States, and here climatic influences or other natural conditions reach the insects during the winter, so that in the spring following only a normal number survive. Cultivating land in crops which admit of fall ploughing is best adapted to Fig. 335. j^iG. 336. The fall army-worm.—5, its Laphygma frugiperda and its head ; c, d, its body segments variations, enlarged. avoid injury, and a frequent rotation will prevent them from be- coming numerous enough to be destructive at any time. The arsenites can be employed, of course, for the protection of crops that admit of being sprayed. Wheat-flelds badly infested in fall are not necessarily ruined or even much injured, because wheat will stand cutting down almost to the ground during the latter part of the season, and will yet come up vigorous and in good condition the spring following. The moth that produces this caterpillar is a modest, gray creature, expanding hardly more than an inch, and the hind wings are pure white and semi-trans- parent. It is a variable species, and ranges from an almost uni- form gray to forms in which there is a considerable admixture of bluish white, the ordinary lines and spots of the owlet-moths being also well marked.
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