30 



BULLETIN" 1320, IT. S. DEPARTMENT OF AGRICULTURE 



Heavy infestation from overwintered weevils is to be expected 

 under normal conditions. The abundant protection afforded by native 

 vegetation and the mild winters of the Sea Island sections afford 

 excellent conditions for successful hibernation. Weevil emergence 

 begins early, the first weevils usually being noted during April, 

 feeding on the growing tips of the young cotton plants. The bulk of 

 the cotton in this district is planted during the latter part of March, 

 and squares begin to appear by the middle of May. 



During 1923 many fields in this section were heavily infested with 

 weevils by June 10, while other fields farther away from favorable 

 hibernation places showed very slight infestation. Hot dry weather 

 during June caused high mortality of weevil larvse in those fields where 

 clean cultivation was practiced and the plants were still small, so that 

 the sunlight could reach the shed squares. Although weevil infesta-, 

 tion was reduced by the natural control factors in June, the appear- 

 ance of a new generation of weevils early in July caused infestation 

 to increase gradually, so that in the fields where control measures 

 were not applied infestation was practically complete by the middle 

 of July. 



<|5 /,3oo 



X S.200 

 Q t/0£> 



COMPARISON OF SUCCESSIVE ADJACENT PLANTINGS AT 



CHARLESTON 



Four successive plantings, as shown in Figure 9, were made on 

 James Island on April 5, 16, 25, and May 4, each planting being in 



duplicate. The arrangement 

 of the plantings was similar to 

 those at San Antonio. Plats 

 numbered 3, 4, 6, 7, and 8 con- 

 sisted of six rows, while plats 

 2, 5, and 9 had seven rows, 

 the additional row being con- 

 sidered as a guard, on account 

 of being adjacent to a much 

 earlier planting. Guard blocks 

 1 and 10 were also planted on 

 each side of the field on April 

 5. The rows were 310 feet 

 long and spaced 5 feet apart. 

 The experiment was planted 

 with seed of a very uniform 

 strain of the Meade variety 

 of Upland long-staple cotton. 

 This variety has a staple 

 length of 1% inches and is 

 adapted for use on the South 

 Carolina Sea Islands. The 

 seed was planted by hand in hills 12 inches apart. The cold 

 dry weather of April delayed germination and caused a slow 

 growth of the early cotton during the seedling stage. With 

 higher air temperatures and adequate moisture in May, growth 

 became more rapid. The plants in each planting were thinned 

 to two to the hill 12 inches apart when they reached a height 



// /& /& ^S ^7 JO 



Fig. 9. — Flowering record of successive plantings of 

 cotton on James Island, near Charleston, S. C, 

 July 11 to August 17 



