AGRICULTURAL BOTANY. 235 



the flame, each of which would have deposited its hundreds of eggs in a few days. If this 

 plan were generally adopted and persevered in for a few successive nights at the proper season, 

 its effect would doubtless be, if not entirely to destroy, at least to diminish to a very benefi- 

 cial extent, these mischievous pests. The first hatching of the caterpillar in the spring could 

 not at first be thus destroyed or their ravages prevented ; but the second brood, if it may be 

 so termed, which is generally considered most numerous and destructive, and which furnishes 

 the eggs for the supply of the succeeding year, would be cut off to a great extent. However 

 this suggestion may be received, it is at least as practicable as any of the plans that have been 

 proposed for the same object, some of which have been promulgated through respectable agri- 

 cultural journals, such as the powdering of the leaves of the plant with finely-pulverized quick- 

 lime, or the fumigation of each separate plant with sulphurous vapor, produced by burning 

 brimstone on chafing-dishes, each plant being enclosed, during the process, in a tight canvas 

 hood, ten minutes being considered sufficient for each plant. If this were at all practicable, 

 one hand, with great diligence, might, at this rate, go over one acre in fifteen or twenty days. 



The caterpillar, which does not usually appear until the cotton-plant is pretty well matured, 

 feeds chiefly upon the leaf, and the degree of damage done depends upon the period it com- 

 mences its depredations. If so early that a few bolls are matured, the plant must cease to 

 grow when stripped of its leaves. Instances have occurred, but, it must be confessed, very 

 rarely, when the growth of the plant was too vigorous, and continued too late in the season, 

 in which a partial cropping of the leaves by the worm has had a beneficial effect in arresting 

 the growth, and causing the bolls to mature and open. If their appearance is delayed until 

 a period iniim'diutely preceding a killing frost, and during a dry season, they confer a benefit 

 in removing the leaf, which after a frost stains the cotton and renders it very trashy by crumb- 

 ling and falling upon it. 



" The boll-worm is comparatively small, resembling at first the silk-worm in its early stages ; 

 its fcttackfl are made within the calyx, and about the base of the boll, which it perforates, and 

 when first forming, or tender, it wholly devours, or causes to drop off. (See Plate.) Wattes' s 

 Report on the Geoloyy of Mississippi. 



The Diseases of the Cotton-Plant. 



THE diseases of the cotton-plant are the rust, the rot, and the sore-shins. 



The first is most probably attributable to the mineral properties of the soil, as it is local 

 and partial in its effects ; and on the spots of ground affected by it, the difference of soil is 

 obvious to the eye. The appearance of the plant so diseased suggests the existence of micro- 

 scopic fungi, which exhaust by their parasitic growth the sap of the leaves, and cause them 

 to wither and fall. 



The rot, or disease of the boll, has been assigned to various causes. The first external in- 

 dication of its approach is the appearance of an almost imperceptible puncture on the side, and 

 generally near the base of the boll, surrounded by a slight discoloration, or change of tint, 

 presenting the semblance of a minute spot of grease a character given it in the common con- 

 versation of planters, in speaking of the disease. (See Plate.) The most received opinion, 

 and that best supported, is, that it is occasioned by the larvse of a small insect which is 

 hatched from the egg deposited in the boll in some unknown manner, at an early stage of its 

 growth, and which, feeding on the succulent and pulpy seeds in their early stage of formation, 

 produces the disease without immediately destroying the boll. This not unfrequently is only 

 partially damaged, and continues to grow nearly to its mature size, becoming in the end 

 externally black and hard ; the decayed state of the interior of the boll presenting an analogy 

 to the peach or plum, which, though often presenting even a fair and perfect exterior, is found 

 upon opening to have been long preyed upon by the curculio or peach-worm. 



It is certain that the diseased and blackened boll, when broken open, reveals a variety of 

 small insects, sometimes in the different stages or conditions of their metamorphosis. Which 

 of these is the real enemy, can only be determined by the close and continued observation of 

 the practical entomologist.* 



* The insect theory in connection with the cause of the rot is sustained hy observations made during the last 

 two years. It has been remarked that on lands where the different varieties of cotton had been planted sepa- 



