22 BULLETIN 564, U. S. DEPAKTMENT OF AGRICULTURE. 



In order to see if these injured forms collected in the bags were 

 reducing the number reaching the ground to any extent, one collec- 

 tion of fallen forms was made in both plats on July 14. For this 

 purpose a strip 20 feet long and three rows wide was laid off in the 

 middle and each end of each plat, and all fallen forms were gathered 

 from these strips. As the rows averaged four and a half feet in width, 

 the total area examined in each plat was 820 square feet. The strips 

 were selected so that no skips in stand were included, and the cotton 

 as nearly as possible represented the average growth of that portion 

 of the plat. As the preceding bag-and-hoop collection had been made 

 on July 10, this fallen form collection was four days after a picking. 

 The results secured are shown in Table 19. 



Table 19. — Fallen forms collected in Hecla plantation experiment, Mound, La., July 



14, 1916. 





Plat. 



Forms gathered. 





Squares. 



Bolls. Total. 



Check 



447 

 234 



23 470 



Picked 



21 ! 255 









From Table 19 it is seen that while the boll collection differed very 

 little, there were 213 more squares collected from the check than from 

 the picked plat. If these figures are taken as a criterion, they show 

 that the bag-and-hoop pickings reduced the forms reaching the ground 

 by 47 per cent. This is a considerably greater reduction than has been 

 found in most of the tests with the 7-day interval, but this difference 

 may well be due to the varietal differences in the cotton. As has 

 already been mentioned, this test was conducted with a long-staple 

 variety which tended to retain a considerable proportion of the in- 

 fested squares. Even the squares which were going to fall were 

 probably sufficiently attached to the plant to remain somewhat 

 longer than would be the case on a short-staple variety, and conse- 

 quently their chance of being collected in the bags was increased. 



One important question in connection with this type of plat work 

 concerns the influence of one plat upon another and also the influ- 

 ence of any near-by untreated cotton on the treated plat. This 

 point, of course, is of primary importance in determining just how 

 nearly such plat tests represent the conditions which would prevail 

 if an entire field was treated in the same manner as the plat in ques- 

 tion. In an effort to secure some information on this point the 

 records of the bag-and-hoop collections of weevils and forms were 

 made by rows as well as by plats. The rows hi the picked plat 

 were numbered from 1 to 22, beginning with the row adjoining the 

 check, and the record for each row was kept separate throughout the 

 iiYe pickings. 



