HOW TO PROFIT BY KXISTTNG CONDITIONS. 89 



EARLY DESTRUCTION OF THE COTTON STALKS. 



Tliero can bo little doubt that tho oaily dostruction of the cotton 

 stalks, in addition to depriving tho boll weevil of its food plant, will 

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

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

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

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

 destruction wore carried out, as discussed in Part I, section 6. As a 

 further proof tlio famous Olivia fall-destruction experiments may be 

 considered. 



On October 1 to 10, 1906, all of the cotton plants in over 400 acres, 

 constituting the entire Ohvia cotton community in Calhoun County, 

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

 According to the roaring records in our possession, the parasites 

 devolo})ing in this cotton would all bo mature before November 10, 

 and if they hibernated, would have to do so as adults. No other 

 cotton existed within 12 miles, as the community is completely iso- 

 lated by water and marshland. 



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

 weevil work could bo found, but on May 7 a single weevil was found 

 after a earoful examination of eight fields. On tho 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 slight 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 j)arasitos with woovil- 

 infosted squares on a field in tho opposite part of the community to 

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

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

 boll weevil's absence. 



Having i)lanned the cropping system, it is also best to prepare the 

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

 of tho reasons for early planting 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 the para- 

 sites to start early. 



Care must bo given to the choice of the cotton variety which is to 

 be used. Frequent recommendations have boon made of varieties 

 with light foliage, early maturing fruit, short nock^s, and determinate 

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



