THE BOLL WEEVIL PROBLEM. 39 
Application of the bisulphid in this manner reduces the elements of danger to 
a minimum, as the vapor is almost wholly confined and the slight quantity 
escaping, mixed with the open air, would not be in either inflammable or 
explosive proportions. It has been determined that the slight trace of bisulphid 
vapor in the air would not injure the operator in the slightest degree. The 
sacks should be left in the box for 40 hours after the gas is injected. 
RELATION OF MEANS OF CONTROLLING THE BOLL WEEVIL TO 
THE CONTROL OF OTHER INSECTS. 
The cotton bollworm.—The most important insect enemy of cotton 
in the United States, aside from the boll weevil, is the bollworm 
(Heliothis obsoleta Fab.). 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 over $8,000,000. In addition to the injury to cotton, 
this insect is a very important enemy of corn, tomato, okra, cowpeas, 
and some other crops. Careful studies of the bollworm were con- 
ducted by Mr. A. L. Quaintance, of the Bureau of Entomology, in 
connection 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 bollworm. 
The following is the statement by Mr. Quaintance on this subject: 
The steps in the production of early cotton, outlined above, include the prin- 
cipal recommendations for the growing of cotton in the presence of boll weevils. 
It is therefore seen that injury from 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 impera- 
tive the adoption of these methods in profitable cotton culture, and along with 
this change the ravages of the bollworm during normal seasons should 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 (Aphis gossypii Glov.), that may occasionally cause unusual 
damage by reason of early planting. This will only happen to any 
appreciable extent during wet seasons. Under such conditions the 
aphis may sometimes make it necessary to replant.' Nevertheless, 
this is not an important difficulty. It is not of sufficient moment to 
be considered at all, in view of the enormous benefit in avoiding dam- 
age by the boll weevil by means of early planting. If the other steps 
in the control of the boll weevil be taken and the fields made clean 
during the winter and the rubbish in the fence corners and along the 
turn rows destroyed, it is not likely that the aphis will do any con- 
siderable damage, even during the coolest and wettest springs. 
1Qn the contrary, cases have been noticed where early breaking and thorough working 
caused a lessening in the number of aphides, due to the destruction of the ant that pro- 
tects them. Mr. Wilson Newell calls our attention to an instance of this kind in Loui- 
siana in 1908. 
512 
