PR 



AC 



The lx>ll weevil has peeh present in the United States for fourteen 

 years. At this time it is doing serious damage to cotton in four 

 States, and during the present season undoubtedly will invade a fifth. 

 In regions like Central America, where the insect has existed for 

 many years, there are various influences that serve to hold it in 

 check. In this country similar influences are beginning to be in 

 evidence. Among the direct factors in the natural control of the 

 boll weevil that are now at work are the following: Heat and dry- 

 ness, the native ant Solenopsis geminata, a winter temperatures, 

 proliferation, parasites, defoliation by the cotton leaf-worm, deter- 

 minate growth, and birds. Of these, proliferation and birds have 

 already received careful special attention, while the work of the 

 native ant has received preliminary notice. The other factors have 

 also been more or less discussed in the publications of the Bureau 

 of Entomology and elsewhere, and more extensive studies of certain 

 ones will be discussed by Dr. W. E. Hinds in Bulletin No. 74 of this 

 Bureau. 



While the work of parasites, discussed in this bulletin, is not at 

 present one of the most important factors in the control of the boll 

 weevil, the indications are clear that its importance will grow rapidly. 

 Moreover, the matter has special interest for the reason that it is 

 not unlikely that practical means may be devised to increase the work 

 of the parasites. 



In the United States fifteen species of insects which seek the weevil 

 in its immature stages are known. These insects have not been 

 introduced artificially from other countries, nor have they followed 

 the boll weevil into this country. They have all been present for 

 years, and have been actively parasitic upon other species of weevils 

 found within the boll-weevil-infested territor}^. In fact, there are 

 a great many closely related weevils of the genus Anthonomus, some 

 of which are very common in parts of the cotton belt. These weevils 

 are frequently held completely in control by parasites, and for the 

 most part the parasites are not confined to the attack of a single 

 species of weevil. In many cases the boll weevil may appear in a 



a Not to be confused with the kelep, the introduction of which has proved unsuc- 

 cessful. 



3 



