133 



BULLETIN OF T 



No. 233 



Contribution from the Bureau of Entomology, L. 0. Howard, Chief. 

 May 27, 1915. 



RELATION OF THE ARIZONA WILD COTTON WEEVIL TO 

 COTTON PLANTING IN THE ARID WEST. 1 



By B. R. Coad, 



Entomological Assistant, Southern Field Crop Insect Investigations. 



INTRODUCTION. 



With the introduction of cotton culture into Arizona under con- 

 ditions of irrigation, it was hoped that the establishment of important 

 insect pests could be prevented by quarantines, and this was ren- 

 dered possible by the complete isolation of the new territory. Recent 

 investigations in Arizona, however, have revealed the presence of a 

 weevil, Anthonomus grandis thurberise, very nearly identical with the 

 famous Mexican cotton-boll weevil which has proved so disastrous to 

 cotton culture in many parts of the South. This is due to the occur- 

 rence, in many of the mountain ranges of the southeastern section 

 of the State, of a wild cotton plant known technically as Thurberia 

 thesj>esioides. This plant, which is so closely related to cotton that 

 some investigators have classed it in the genus Gossypium (the genus 

 of cotton), was found to be the host of a weevil closely related to the 

 cotton-boll weevil, as well as the host of a number of other insects, 

 and it was at once perceived that there was a possibility that these 

 insects might attack cultivated cotton grown near these mountains. 

 Of the various insects found on the wild cotton plant, the weevil is 

 probably the most important, and the present bulletin deals with 

 this snecies. 



HISTORY OF THE WEEVIL. 



While the history of the cotton-boll weevil is a familiar subject to 

 almost every one in the infested territory, it is not nearly so well 

 known in the western cotton country, and a brief review of its activi- 

 ties in the United States will help to an understanding of the sig- 

 nificance of its presence in Arizona. 



The Mexican cotton-boll weevil, Anthonomus grandis Boh., came 

 into the United States from Mexico, crossing the Rio Grande at 



1 The investigations on which this paper is based were conducted under the direction of Mr. W. D. 

 Hunter. 



89031°— 15 



