COTTON IN WEEVIL-CONTROL EXPERIMENTS 21 



The rows in this test were divided into two 100-foot sections by 

 a line stretched across the field, and the weight of seed cotton was 

 recorded from each section of each row. Section A includes the 

 western half of the field and section B the eastern half, where the 

 plants were notably larger. The weight of seed cotton and the 

 number of plants are stated in Table 12. These data are also shown 

 graphically in Figure 7. In comparing the yields of the four plant- 

 ings the weight of seed cotton from only the four inside rows of each 

 block is used. The yields of the outside rows vary to a considerable 

 extent, being affected by adjoining blocks of earlier or later planted 

 cotton. 



The highest yield of seed cotton was obtained from the April 19 

 planting, the yields from three 4-row blocks having been 51.39, 46.62, 

 and 43.81 pounds, respectively. The yields from the April 28 and 

 May 5 plantings were about equal. Two blocks of the April 28 

 planting yielded 35.28 and 35.21 pounds, while the May 5 planting 

 produced 35.31 and 36.56 pounds. Very low yields were recorded 

 from the May 12 planting, the two blocks having produced only 12.06 

 and 13.92 pounds of cotton, respectively. 



Consistent differences in the yield of the east and west sections of 

 rows occurred in all plantings. The lower yields from the west sec- 

 tion of rows were due to the presence of Johnson grass, which retarded 

 the growth of plants in this part of the field. 



In the May 12 planting no thinning was done in parts of rows 

 where a stand was obtained, so that the plant counts are not com- 

 parable with those obtained from the other plantings. Though the 

 low yields of the May 12 planting may be ascribed very largely to 

 the poor stand of plants, the larger proportion of bolls injured by the 

 weevils was also a factor. 



The higher yields obtained from the cotton planted on April 19 

 may also be ascribed, at least in part, to the smaller percentage of 

 injured bolls, showing that the weevil conditions were not as severe 

 during the early period of boll development. 



Nearly the same numbers of flowers and shed bolls were recorded 

 from the April 19, April 28, and May 5 plantings, and the totals of 

 the yields from the four 50-foot sections of rows of each planting 

 from which these records were obtained were nearly the same, having 

 been 12.68 pounds from the April 19 planting, 12.15 pounds from the 

 planting of April 28, and 11.67 pounds from that of May 5. Never- 

 theless, the total block yields were considerably higher on the. April 

 19 planting. 



It seems possible that the higher yields obtained from the 50-foot 

 sections of rows in the April 28 and May 5 plantings, as compared 

 with the total block yields, may have been due to the fact that all 

 of the weevil-infested squares were picked up under the 50-foot sec- 

 tions during July for record purposes. 



The additional protection that may have been given to the 50-foot 

 sections by collecting the weevil-shed squares would not render the 

 yields less significant. On the contrary, the yields that were secured 

 from these sections of rows may be more indicative of the results that 

 might have been secured if the later plantings had been apart from 

 the earliest planting and bad not been subjected to the weevil infesta- 

 tion from the early cotton. 



