136 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 



worms can be disturbed and knocked down or brushed off from the 

 plants lias, to some extent, a beneficial influence in lessening the num- 

 ber of the worms, the explanation being that once on the ground they 

 can be crushed in some way or that they are very liable to the attacks 

 of the ants. In very hot and dry weather the knocked-off worms are 

 very often unable to regain the plant, and perish on the hot soil. Thus, 

 frequent cultivating and working of the cotton wiU have some benefi- 

 cial effect in this regard, and a number of contrivances have been sug- 

 gested to expedite this mechanical method of killing the worms. One 

 of the best, in the words of Dr. J. T>. Hoyt, of Livingston, Ala.,* "is to 

 drag something like a piece of cotton-bagging along over the rows of 

 cotton, forward and back, which may be long enough to extend across 

 several rows, and having short lines attached to one edge, a little fur- 

 ther apart than the width of the rows, and a hand at each line, and all 

 abreast i)ass along between the rows, and then back j when the brush- 

 ing and shaking of the stalks by the bagging will clear the cotton 

 mostly of the worms. In this way a set of hands can go over their crop 

 in a day or two, when they should return to the beginning aud go over 

 again, and continue so doing as long as any number of worms are found 

 on the stalks." At best, however, only a portion of the worms are 

 knocked off, for no amount of shaking or brushing, even when violent 

 enough to injure the plants and knock off' the bolls, will dislodge all the 

 worms, and particularly will not disturb most of the young ones. 



As this subject will, however, be treated of in its proper place in 

 Chapter XIII, we will pass at once to the consideration of the sub- 

 stances which may be employed against the worm. 



POISONING THE WORMS. 

 MINERAL INSECTICIDES. 



With the introduction of mineral poisons for the destruction of the 

 worms a new impetus was given to the invention of machines and con- 

 trivances for the application of these ])oisons either as powder or in 

 water. The large number of such inventions that have been perfected, 

 and the activity still displayed in adding improvements, furnish evi- 

 dence that this poisoning of the worms has so far proved most satis- 

 factory in protecting the crop. The fact is tbat a judicious and timely 

 application of the best poison will always, even under unfavorable con- 

 ditions and in bad '^ worm years," enable the energetic planter to save 

 at least the larger portion of his crop. 



The progress in improving the quality of the insecticides already in 

 use, and the discovery of new and more effectual ones, is slower than 

 the invention and improvement of machinery, because of the numerous 

 difiaculties in thoroughly testing any remedy in the field, the most seri- 

 ous being the great susceptibility of the cotton plant to injury by some of 



* Practical Modes of Destroying the Cotton Worm ; A Prize Essay. Selma, Ala., 1874. 



