FIBER CROPS 



359 



Map showing the distribution of the cotton- 

 boll weevil up to 1 905 



As in the case of cereal crops, the most practicable method 

 of combating in a large way insects injurious to cotton are a 

 rotation of crops, thorough cultivation and general cleanliness 

 of surroundings, which prevents the successful hibernation of 

 the insects and de- 

 creases their opportu- 

 nity for getting sus- 

 tenance from volun- 

 teer plants. Cut- 

 worms are sometimes 

 destructive by cutting 

 off the young cotton 

 plants. Trapping with 

 poisoned green vege- 

 tation such as grass or cabbage placed here and there through 

 the field has been found effective. (C. A. 329) 



454. THE MEXICAN COTTON-BOLL WEEVIL has gradually been spreading 

 northward throughout Texas until at the present time it has spread over much 

 of the cotton belt of Texas. The adult is a small grayish weevil less than a 

 quarter of an inch in length while the larva which does the damage is nearly 

 when full grown of equal length. The insects pass the winter in the adult 

 state. In the spring they lay their eggs upon the buds, and later upon the 

 bolls of the cotton plant, into which the larvae upon hatching bore and feed. 

 It is a rule that buds which are attacked drop off while the bolls do not. 

 In either case the injury is complete. There are a number of generations in 

 a season, about two weeks being required for development from egg to adult, 

 hence the injury is greatest in the latter part of the season and upon the 

 later maturing plants. It is estimated that the progeny of a single pair in a 

 season may amount to 134 million individuals. 1 



The method of combating this pest consists in reducing the number of 

 insects in the fall by the early destruction of the plants, and in hastening 

 the maturity of the plant by all available means, such as early planting, using 

 early varieties or northern grown seed, use of fertilizers, thorough cultivation 

 and proper spacing of plants. The plants should be plowed up in the fall 

 as early as the crop will permit, and burned. In some cases pasturing with 

 cattle may be effective. Each season's infection is more or less local since 

 the adults do not travel rapidly, hence the measures above proposed are of 

 value even though neighboring planters do not practise them. While care 



1 U. S. Dept. Agr. Yearbook 1903, p. 205. 



