THE BOLL-WEEVIL PROBLEM. 33 



Application of the disulphid in this manner reduces the element 

 of danger to a minimum, as the vapor is ahnost wholly confined, and 

 the slight quantity escapmg, mixed with the open air, would not bo 

 in either inflammable or explosive proportions. It has been deter- 

 mined that the slight trace of disulphid vapor in the air would not 

 injure the operator in the slightest degree. The sacks should be left 

 m the box for 40 hours after the gas is injected. 



RELATION OF METHODS OF CONTROL OF THE BOLL WEEVIL TO THE CONTROL OF 

 OTHER INSECTS. 



TTie cotton hollworm.—Th.e most important insect enemy of cotton 

 in the United States, aside from the boll weevil, is the bollworm.^ 

 This pest has existed in this country for many years and frequently 

 reduces the crop very considerably. The annual damage to cotton in 

 the United States has been conservatively estimated at more than 

 $8,000,000. In addition to the injury it does to cotton, this insect is 

 a very important enemy of corn, tomato, okra, cowpeas, and some 

 other crops. Careful studies of the boUworm were conducted by Dr. 

 A. L. Quaintance, of the Bureau of Entomology, in coimection with 

 large-scale field experiments in many localities. The conclusions 

 drawn from this practical work were that the essential steps to be 

 resorted to in the control of the boll weevil are exactly the ones that 

 should be followed in the warfare against the boUworm. The fol- 

 io wmg is the statement by Dr. Quaintance on this subject: 



The steps in the production of early cotton, outlined above, include the prin- 

 cipal recommendations for the gro\?ing of cotton in the presence of boll weevils. It 

 is therefore seen that injury Irom the cotton bollworm and the cotton boll weevil 

 may be best avoided by the adoption of one and the same course of improved farm 

 practice. The spread of the latter species will render imperative the adoption of 

 these methods in profitalde cotton culture, and along with this change the ravages of 

 the bollworm during normal seasons slioiild become less and less. 



The cotton aphis. — Of the numerous minor enemies of the cotton 

 plant in the United States there is one, the cotton aphis, or plant- 

 louse, that occasionally may cause unusual damage by reason of 

 early planting. This will happen to any appreciable extent only 

 durmg wet seasons. Under such conditions the aphis sometimes 

 may make it necessary to replant.^ Nevertheless, this is not 

 an important matter. It is not of sufficient moment to be con- 

 sidered at all, in view of the enormous benefit in avoiding dam- 

 age by the boll weevil by means of early planting. If the other stops 

 in the control of the boll w^ec^'il be taken, the fields made clean 

 during the winter, and the rubbish in the fence corners and along the 



' Chloridea obsoleta Fab. 



2 Aphis gossypii Glov. 



3 On the contrary, cases have been noticed where early breaking and thorougli working caused a lessening 

 in the number ofaphids, due to the destruction of t he ant that protects them. Mr. Wilmon Newell calls 

 attention to an instance ol ihis kind in Louisiana in 1908. 



