CHAPTER X. DISEASES OF THE COTTON PLANT. SECTION I. DISEASES RESULTING SOLELY FROM INSECTS. THE Cotton world is greatly indebted to Mr. T. Glover for his researches into the diseases of our valuable plant. We present the result of his labors without offering any apology. INSECTS FREQUENTING THE COTTON PLANT. The cotton plant furnishes food for numerous insects, some of which feed exclusively upon the leaf, some upon the flower, while others destroy the young buds and bolls. It is my purpose to describe these insects, not in the order of their classification by natural families, but according to the part of the plant they most generally frequent, or to which their ravages are chiefly confined. Thus, by referring to the parts injured, one can easily recognize the insects, or their larvæ, which attack them in any of the stages of their existence. Many of these insects at first appear in small numbers, and only become formidable in the second or third gener ation; for instance, if a female boll-worm produce five hundred moths, one-half of which are males and the other half females, the next generation, if the increase be in the same ratio, will amount to one hundred and twenty-five thousand caterpillars or moths; and all this is accomplished in the space of a few weeks. It will therefore be perceived that their destruction depends upon prompt and timely action; and planters may materially aid in carrying out a work designed for their mutual benefit, by minutely observing the habits and characteristics of these pests of our fields, devising means for their destruction, and communicating the results of their observations and experiments, through some appropriate channels, to the public. Insects injurious to the cotton plant consist of those very destructive to the general crops, such as the bollworm, cotton caterpillar, and some others; and those which do comparatively little injury, their numbers thus far not being sufficiently great to cause much damage, such as the leaf-rolling caterpillar (Tortrix) and several insects hereafter mentioned. There are still others, which do not materially injure the crop itself, such as the spanworm, and others which only feed upon the petals or pollen of the flowers. There are also many insects found in the cotton fields which do no damage whatever to the plant, but merely feed upon weeds and grass growing between the rows, such as the caterpillar of the Argynnis columbina, which feeds upon the passion-vine, and that of the Zanthidia niceppe, which sometimes devours the Maryland cassia, and produces the beautiful orange-colored butterflies, seen in vast numbers hovering over moist or wet places on the plantations. A class of insects which is highly beneficial, comprehends the larvæ of the lady-bird, the ichneumon flies, and |