COTTON IN WEEVIL-CONTROL EXPERIMENTS 



No squares were removed that were less than 10 days old, at which 

 time the involucre of the square was about three-eighths of an inch 

 in length. It was found to be impossible to remove squares smaller 

 than this without breaking the tips of the fruiting branches or injuring 

 the terminal buds of the plants. Records were obtained of the 

 number of squares picked from four rows in the April 19 and April 28 

 plantings. The number of plants to the row and the number of 

 squares removed from each row are given in Table 4. 



Table 4. 



-Number of squares removed on June 12 from cotton plants of the first 

 and second plantings in rows 200 feet long at San Antonio 



Date planted, 1923 



Number 



of plants 



to the 



row 



Number 

 of squares 

 removed 



Average 



number 



of squares 



to the 



plant 



Date planted, 1923 



Number 



of plants 



to the 



row 



Number 

 of squares 

 removed 



Average 



number 



of squares 



to the 



plant 



Apr. 19 J 



392 



375 



403 

 387 



787 

 803 

 823 

 734 



2.0 

 2.1 

 2.0 

 1.9 



Apr. 28 ! 



300 

 261 

 285 

 334 



128 

 146 

 114 

 193 



0.4 



.6 

 .4 

 .6 



An average of two squares removed from each plant corresponds 

 to the amount of stripping reported in experiments with the stripping 

 method in Florida. 3 A difference of nine days in the planting date of 

 the first and second plantings resulted in only one-fourth as many 

 squares being removed from the second planting as from the first. 

 In plantings which were deferred until May 5 and May 12 there was 

 no necessity of square removal to avoid infestation by overwintered 

 weevils. 



The average time required for finding and removing squares was 

 48 minutes per row in the April 19 planting and 22 minutes per row 

 in the planting of April 28, the length of rows being 200 feet. On 

 this basis the time required to strip an acre was estimated at 41 hours 

 for the first planting and 19 hours for the second. At the rate of 

 four days per acre, or even two days, the labor requirement for square 

 stripping is considerable. 



Only 2 weevils were found in squares removed from the two blocks 

 of the second planting, while 96 weevils were caught in the three 

 blocks of the first planting. The fact that so few weevils were 

 caught in the second planting is probably due to the smaller number 

 of large squares on the later plants. Weevils which are feeding on 

 the floral bud inside the involucre of large squares are more likely to 

 be caught. 



A hundred squares from each row in the April 19 and April 28 

 plantings were examined, in order to determine the percentage of 

 squares that had been punctured. The records of punctured squares 

 in each block of the first planting gave the following average per- 

 centages of infestation: Block 1, 23; block 2, 14; block 3, 12. The 

 first block of the second planting had 9.7 per cent and the second block 

 had 6.5 per cent of the squares punctured. 



Calcium arsenate in dry-dust form was applied to the entire field 

 immediately following the removal of squares from the first two 



1 Jmlth, (i. D. A preliminary report upon an improved method of controlling the boll weevil. Fla. 

 Agr. Exp. Sta. Bui. 166, 72 p., illus. L922. 



