COTTON" BOLL- WEEVIL CONTROL IN THE MISSISSIPPI DELTA. 3 



during this same period. None of these operations could be neglected 

 without a serious loss to the plantation. As these all fall at the time 

 when it is necessary to perform the weevil-picking or square-picking 

 operations it has become more and more necessary to determine the 

 actual benefit derived from these control measures and to ascertain 

 to what extent it would be profitable to slight the other operations 

 in their favor. A series of studies was, therefore, inaugurated at the 

 Delta Laboratory located at Tallulah, La., in the effort to secure 

 definite information on these points. These studies were largely con- 

 ducted on an experimental basis, but their results were checked by 

 observations on the plantation use of the different control measures. 

 The following is a brief consideration of the points brought out by 

 these studies. 



SQUARE PICKING. 



The first of the studies consisted of plat tests on the effect of pick- 

 ing only the fallen forms during the spring. The first picking was 

 made as soon as the fallen forms had reached a considerable number 

 and still before the weevils had started to emerge from them. As 

 the emergence of the weevil from hibernation was exceedingly late 

 during the season when this test was conducted (1915), it did not 

 prove necessary to conduct this first picking until June 16. Of 

 course this date of picking would vary widely with the season, and 

 in a year of normal emergence it would undoubtedly be much earlier. 

 Following this the plat was carefully picked over every 7 days 

 until July 14, a total of five pickings, extending over a period of 28 

 days. During this time 42,672 forms per acre were collected. In 

 actual bulk this equaled about 42 gallons per acre. The method of 

 picking used was the simplest possible. Mixed negro laborers were 

 provided with sacks for holding the forms and were sent down the 

 rows to gather all forms from the ground by hand. The picking 

 was carefully supervised in order to make sure that the collections 

 were thorough. 



The weevil infestation in these plats was followed carefully 

 throughout the season and it was soon found that the infestation in 

 the picked plat was showing a very decided effect from the operation. 

 For example, on July 6, 18 per cent of the squares in the picked plat 

 were infested, while 44 per cent were infested in the untreated check 

 plat. On July 13, the percentages were 37 and 63, respectively. In 

 fact all observations consistently demonstrated that the square col- 

 lection was reducing the weevil infestation within the treated plat. 

 Of course the final criterion determining the effect of the operation 

 was the production, and it was found that the picked plat produced 

 23 per cent more seed cotton per acre than the check. However, this 



