INSECTS INJURIOUS TO COTTON 243 



until cotton appears. The length of time occupied in the dif- 

 ferent stages is seen to be quite variable, but is approximately 

 six days for the egg, twenty days for the larva, and thirteen days 

 (usually ten to fifteen days) for the pupa making a total of 

 about forty days for the complete life cycle. Dr. Chittenden 

 believes that there are two generations in the North and probably 

 three in the latitude of the District of Columbia. 



Control. This species has not been sufficiently injurious on 

 cotton to warrant extensive experiments in its. control. Where 

 it attacks young plants of cotton or other crops, it may be com- 

 bated with the means suggested for other cutworms. Where 

 it becomes injurious to the bolls, it might be controlled by thorough 

 dusting or spraying with arsenicals, which would destroy the 

 young larvae while they are still feeding on the foliage. 



The Mexican Cotton Boll Weevil * 



Not since the invasion of the Mississippi Valley by the Rocky 

 Mountain locusts in the 70's has any insect caused such ruin 



FIG. 206. The cotton boll weevil, natural size, showing variation in 

 size and color. 



to any staple crop as has the boll weevil in the territory affected 

 during the past twenty years, and it is one of the factors in the 

 recent high prices of cotton. 



Like several of the worst insect pests of the South it is a native 

 of Central America and came to us from Mexico, crossing the 

 Rio Grande at Brownsville, Texas, about 1890. As early as 1862 

 the weevil caused the growers at Monclova, Mexico, to abandon 

 cotton culture and when they again planted it in 1893, the beetle 

 promptly appeared and destroyed the entire crop. It multiplied 



* Anthonomus grandis Boh. Family Curculionidae. See W. D. Hunter. 

 "The Boll Weevil Problem," Farmers' Bulletin 848, U. S. Dept. Agr.; and 

 Hunter and Hinds, Bulletin 51, Bureau of Entomology, U. S. Dept. Agr. 



