ITLE BOLL- WEEVIL PEOBLEM. 35 



recent work with powdered arsenate of lead by ;Mi\ Wilmon Newell, 

 formerly of the Louisiana State Crop Pest Commission, seems to 

 show that this poison can be used with profit when the plants are 

 small and the weevils abmidant. Experiments performed in Louisi- 

 ana in 1909 showed that cotton treated with powdered arsenate of 

 lead jaelded an average of 71 per cent more than similar cotton which 

 was n.ot treated. For several years the Bureau of Entomology has 

 been experimenting with this poison. In many cases its use has 

 resulted in increased yields more than sufficient to offset the cost of 

 the application. In other cases there has been a loss. It is evident 

 that under some circumstances the poison can be used with profit by 

 the planter. Experimental field work now mider way in Louisiana is 

 expected to show the exact practical application of this or other 

 poisons in the control of the boll weevil. 



Sweetened poisons.- — ^Many attempts have been made to cause 

 poisoned substances to be attractive to the weevil by introducing 

 sweets and other ingredients. All these have failed completely. 

 Some Ivnown sweets, such as honey, have a slight attraction for the 

 weevil, but not enough to assist in practical control, even regardless 

 of their expense. 



Contact poisons. — Poisons designed to kill the weevils by suffocating 

 them rather than by being taken hito the digestive organs have been 

 proposed. They can not, of course, be effective against the immatiu-e 

 weevils within the cotton fruit. The difficulties in reaching the adults 

 are in their manner of work. NoiTuaUy these insects are fomid inside 

 the bracts of the squares, where they can not be reached by sprays. 

 In fact, nature designed the bracts to prevent the heaviest rains from 

 reaching the square within. An additional difficulty is in the expense 

 of applying sprays, not only on account of labor, but on accomit of 

 the special machinery that is necessary. Although there is some very 

 remote possibility that dry poisons may be found of assistance in con- 

 troUing the weevil, on accomit of the facts mentioned it is not at all 

 probable that liquid sprays can ever be used. 



Effect of confinement. — There is one peculiarity of the weevil that 

 has led to many unwarranted claims as to the efficacy of remedies. 

 The msect will die within a very short time when confined in a bottle 

 or jar, or even in a cage. Even when cages are placed over gi'owing 

 plants it is fomid that numbers of the insects die and fall to the 

 groimd, though no poison has been applied. In many instances ex- 

 perimenters have applied their preparations under such conditions 

 and have fomid dead weevils later. They have made no allowance 

 for the weevUs that would have died uPider these conditions without 

 any treatment whatever. In such experimental work special pahis 

 should always be taken to provide one or more careful checks upon 

 the weevils that have been subjected to treatment. 



