CONTROL OF BOLL WEEVIL IN MISSISSIPPI DELTA. 27 



other factors than the weevil picking itself were operating to influence 

 the production of these two plats. The factor of drainage has been 

 mentioned as seriously injuring a portion of the check plat. In fact, 

 this injury probably was sufficient practically to account for the 

 results secured. In addition to this, the factor of boll rot must be 

 considered. The exceedingly wet weather of July caused an exces- 

 sively rank plant growth on all highly nitrogenous land, such as that 

 on which these plats were located, and this resulted in the rotting of 

 many of the lower bolls which could not be reached by the sunlight. 

 It has been shown that, while the shaking operations were reducing 

 the fruiting of the plants, they also tended to prevent a rank plant 

 development. As a result, there was little or no boll rot in the 

 picked plat, while the check was injured seriously by this factor. 

 Consequently it is seen that, while the shaking operation actually 

 reduced the fruit set in the picked plat, the reduction in foliar devel- 

 opment served to offset this by preventing boll rot. 



Taking these two factors of boll rot and poor drainage of the check 

 plat into consideration, it is possible to understand why the check 

 matured less cotton than the picked plat in spite of the fact that it 

 actually set more bolls per plant on the poorly drained portions of 

 the plat. To check the production record a bur count was made in 

 both plats by examining 500 plants in each on October 31. At this 

 time it was found that the check plat averaged 7.4 burs per plant, 

 while the picked plat averaged 8.7 per plant. Thus it is seen that 

 the bur count corresponded fairly well with the production record of 

 the two plats. This tends to place further emphasis on the probable 

 accuracy of the boll count. 



At any rate, regardless of the explanation of the weights secured, 

 the fact remains that the difference in favor of the picked plat was 

 so small as to constitute an economic loss, and the utter absence of 

 evidence of a reduction of the infestation of the picked plat due to 

 the pickings makes this test decidedly unfavorable to weevil picking 

 as a means of control. 



EUREKA PLANTATION EXPERIMENT NO. 1. 



The more extensive Eureka test was located in a cut of cotton 

 extending along Walnut Bayou. The series consisted of five plats, 

 each plat extending at right angles to the bayou. The soil on which 

 these plats were located was a rather light sandy loam on the bayou 

 front, grading off heavier toward the back of the cut. As practically 

 all soil gradation in this cut was from north to south, and as it was 

 fairly uniform from east to west, the plats should have been reason- 

 ably comparable as regards the soil, since each extended through 

 the extreme variation. To safeguard further against soil variations 

 two check plats were selected, one on the east side of the series and 



