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« 

 A certain bacterial disease is worthy of note as an important natu- 

 ral factor in bollworm control. As a rule the disease develops among 

 the larger larvae and a larger percentage of larvae usually die in corn 

 ears than upon cotton; this is probably due to the fact that more 

 moisture is present in the corn ears than in the small fruit of cotton 

 where the larvae feed. From 2 to 50 per cent of larvae taken on corn 

 and cotton and kept in the laboratory have been found to die of this 

 disease. Examination of several thousand ears of corn during July 

 showed that from 1 to 5 per cent of the larvae found therein had suc- 

 cumbed to this disease. 



RECOMMENDATIONS. 



The investigations conducted by the Bureau of Entomology during 

 the past three years show that by the general adoption of the several 

 means of control herein described losses from the bollworm may be 

 largely prevented, even during years of severe injury. 



The fact that bollworms do not become numerous in cotton until 

 the hardening of the early corn about August 1 is the basis for the 

 recommendation of certain cultural methods not only advantageous 

 in the presence of the bollworm and boll weevil, but desirable prac- 

 tices in cotton growing regardless of insect enemies. These methods 

 are as follows: 



(1) Thprough plowing of the land during the fall and winter. 

 This operation is not only the means of destroying many bollworm 

 pupae, but is of importance from an agricultural standpoint, in ex- 

 posing the soil to the actions of rain and frost, thus helping to 

 break up its constituents and render them more readily dissolved and 

 consequently available for plant food. Fall plowing is also a requi- 

 site for early planting. 



(2) The use of early fruiting varieties of cotton. 



(3) The use of fertilizers to hasten and increase fruit production. 



(4) Planting the crop as early in the spring as practicable. 



(5) Early and frequent chopping and cultivations. 



Along with the improved farm practices above outlined, the cotton 

 crop may be materially protected by the use of corn and cowpeas as a 

 trap crop (as described on pages 18-19). That the greatest benefit 

 may be derived from the use of the trap crop system it is urged that 

 each farmer in a neighborhood plant at least a few acres of June corn 

 and cowpeas about the 1st of June. 



The use of arsenical poisons upon the cotton will be found of value 

 in proportion to the severity of bollworm attack. Paris green is 

 recommended at the rate of about 3 pounds per acre, applied in the 

 dust form, either pure or diluted with lime or flour. Application by 



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