12 BULLETIN 564, U. S. DEPARTMENT OF AGRICULTURE. 



From Table 9 it is seen that a uniformly low infestation prevailed 

 in these plats during the entire month of June, and it was not until 

 the record of July 11 that any significant difference in the infesta- 

 tion of the various plats appeared. Even then the difference was 

 rather irregular, though it showed that plats 5 and 6 and the two 

 checks were becoming more rapidly infested than the remainder. 

 This same condition prevailed at the examination made July 19, 

 but by July 26 the difference had been more or less neutralized, and 

 from that time onward the only consistent difference was the slightly 

 higher record of the checks above the picked plats. Taking the 

 seasonal average of the various plats, it is seen that plats 1 and 4 

 were practically equal, while plats 5 and 6 showed a slight increase 

 of about 3 per cent and 5 per cent, respectively, while the two checks 

 were slightly higher still. These figures would seem to indicate 

 that, even in the exceedingly small plats under consideration, the 

 pickings of three times a week or more tended to reduce the degree 

 of weevil infestation. 



EFFECT OF SHAKINGS ON PLANT DEVELOPMENT. 



Rather early in the season it was observed that the shakings 

 were apparently having a decidedly pronounced effect upon the 

 growth of the plants in the various plats. It was noted that the 

 plants in the most frequently shaken plats were apparently standing 

 still as far as growth in height was concerned and that the more 

 frequent the shaking the more pronounced this effect. 



One method of measuring this effect was a series of studies on the 

 average height of the plants, which was determined by measuring 

 20 plants in each row and taking the average. The first measure- 

 ment was made on June 13, when it was found that the plants were 

 more or less uniform in height, the range being only from 14.7 inches 

 to 20.2 inches. At this time it was noted that the 15th to 18th 

 rows (plats 4 and 5) were lower than the remainder. This was due 

 to a slight dip in the land extending over these four rows, which 

 had a tendency to retain standing water and thus somewhat retarded 

 plant growth. This tended to reduce the average of these two 

 plats, as will be noted in Table 10, which gives average heights of 

 the plats and rows. Other than this slight difference the growth 

 was very uniform over the series of plats. 



