HOW TO PROFIT BY EXISTING CONDITIONS. 89 



EARLY DESTRUCTION OF THE COTTON STALKS. 



Tlioro can bo little chuibt that tlio oaily (h^struction of tho cotton 

 stalks, in addition to depmdng the boll weevil of its food plant, will 

 also cause tho parasites to seek a series of hosts which can carry them 

 through tlie winter period. In order to prove that fall destruction 

 does not have an injurious effect upon parasite control, wo would cite 

 the discussion of the Victoria fields, in which various methods of fall 

 destruction were carried out, as discussed in Part I, section G. As a 

 further proof the famous 01i\da fall-destruction experiments may be 

 considered. 



On October 1 to 10, 1906, all of the cotton i)lants in over 400 acres, 

 constituting the entire Ohvia cotton community in Callioun County, 

 Tex., were cut and burned under the direction of Mr. J. D. Mitchell. 

 According to the rearing records in our possession, the parasites 

 developing in this cotton would all be mature before November 10, 

 and if tlie}^ hibernated, would have to do so as adults. No other 

 cotton existed within 12 iTiiles, as the communit}^ is completely iso- 

 lated by water and marshland. 



Cotton was planted about March 15, 1907. On April 15 no boll- 

 weevil work could be found, but on INIay 7 a single weevil was found 

 after a careful examination of eight fields. On the same date at Six 

 Mile settlement, across the bay near Port Lavaca, there was consider- 

 able infestation. If the parasites hibernated as adults they would be 

 dead long before the middle of June. If they could have hibernated 

 as immature stages they would have matured by March 15, and under 

 normal conditions three generations would have passed by June 15. 

 The infestation was still very shght in July. It must be argued, 

 therefore, that any boll-weevil parasites must be breeding on some 

 other weevil, if they did not perish. 



On August 22, 1907, Mr. Mitchell found i)arasites with weevil- 

 infested squares on a field in the opposite part of the community to 

 that in which ho first found tho weevil infestation. The obvious 

 inference is that a^ rotation of hosts occurred during tho period of the 

 boll weevil's absence. 



Having planned tlie cropping sj^stom, it is also best to prepare the 

 fields early for cotton and plant as early as possible. Of course, most 

 of the reasons for early ])lanting of cotton are well known and the 

 practice is very common, but in this connection it must bo said that 

 such early planting has the actual advantage of enabling tho para- 

 sites to start early. 



Care must be given to the choice of tlio cotton variety which is to 

 be used. Frequent recommendations have been made of varieties 

 with fight foliage, oarly maturing fruit, short nodes, and determinate 

 growth. All of these quahties are favorable to parasite control, 



