INSECTS INJURIOUS TO COTTON 231 



maggots enter the worm and feed upon its juices. It changes 

 to a pupa as usual, but the pupa soon dies, and large numbers 

 are thus killed. Several similar parasites prey upon the cotton 

 worm, and it is to be regretted that we know of no way of encourag- 

 ing their valuable work. The common insectivorous birds eat 

 large numbers of the worms, especially when they are scarce 

 in early spring, and they should be protected by enacting and 

 .enforcing most stringent laws against their wanton destruction. 



Control. The most commonly used and effective remedy is 

 to dust the plants with arsenate of lead. Dusting machines drawn 

 by a team which will cover four rows at once are in common use. 

 The dust may be applied with any of the powder guns, but it is 

 most commonly applied to two rows at once by means of bags 

 fastened at the ends of a pole and carried by a man on horseback, 

 who can thus dust 15 to 20 acres per day. These sacks are about 

 10 inches long by 4 inches in diameter, open the whole length 

 on one side and firmly sewed at the ends. Eight-ounce Osnaburg 

 is the best cloth for the purpose. A strip of oak or strong wood 

 about 1/^x2 inches, and 5 feet long, has a 1-inch hole bored 

 through it 5 inches from each end, and to this the sack is tacked, 

 fastening one of the edges of the opening to each of the narrow 

 sides of the pole. The sacks are filled through the holes in the pole. 

 When freshly filled a slight jarring will shake out a sufficient 

 amount of the poison, but when nearly empty the pole should 

 be frequently and sharply struck with a short stick or spaces 

 will be missed. The poison has been found most effective with- 

 out the admixture of flour, but if it is used, lighter cloth should 

 be used for the sacks. 



Besides the general use of poisons there have been several 

 important factors which have aided in the control of the cotton 

 worm, so that it is by no means as much of an enemy of the cotton 

 crop as formerly. Among the most important of these, both 

 from an entomological and general agricultural standpoint, is 

 the diversification and rotation of crops, now coming to be more 

 and more practiced by the progressive agriculturists of the South, 

 This alone largely prevents the rapid spread of the pest. Since 

 the seed has become such a valuable product of cotton, smaller 

 varieties with many seeds and a short fibre are being grown, 

 in contrast to the rank-growing, long-fibre sorts formerly pre- 



