CONTROL OF BOLL WEEVIL IN MISSISSIPPI DELTA. 



13 



Table 10.— Average height of plants in each row and plat on June 13, Eureka plantation, 



Tallulah, La., 1916. 



Plat number. 



Row No. 

 1. 



Row No. 

 2. 



Row No. 

 3. 



Row No. 

 4. 



Plat aver- 

 age. 



1 



Inches. 

 18.3 

 15.0 

 15.7 

 17.2 

 12.7 

 19.0 

 19.8 

 18.1 



Inches. 

 14.7 

 17.1 

 16.5 

 15.1 

 14.2 

 16.2 

 21.4 

 19.2 



Inches. 

 16.1 

 18.6 

 16.6 

 12.8 

 15.6 

 17.2 

 20.2 

 20.0 



Inches. 

 15.7 

 16.2 

 19.5 

 13.8 

 19.5 

 15.6 

 19.5 

 19.7 



Inches. 

 16.2 



2 



16.7 



3 



17.0 



4 



14.7 



5 



15.5 



6 



17.0 



Check 1 



20.2 



Check 2 



19.2 







On July 15, just about one month later, similar measurements 

 were made in these same plats and it will be seen from Table 11 

 that very different results were secured. 



Table 11. — Average height of plants in each plat, Eureka plantation, Tallulah, La., 



1916. 



Date measured. 



Plat 1. 



Plat 2. 



Plat 4. 



Plat 4. 



Plat 5. 



Plat 6. 



Check 

 1. 



Check 

 2. 



June 13 



Inches. 

 16.2 

 19.8 



Inches. 

 16.7 

 23.1 



Inches. 

 17.0 

 25.4 



Inches. 

 14.7 

 25.5 



Inches. 

 15.5 

 29.2 



Inches. 

 17.0 

 34.7 



Inches. 

 20.2 

 37.4 



Inches. 

 19.2 



July 15 



44.3 







Plat 1 was far the lowest in height, and there was a regular increase 

 in height with the lessening in the number of shakings, the two checks 

 being highest of all. Of course, at this time the factor of the deter- 

 minate growth due to soil had become somewhat effective, and it will 

 be noted that check 2 averaged 7 inches taller than check 1. This 

 would tend to make the plants grade gradually in height from plat 1 

 to plat 6 regardless of their treatment, but the grading was far more 

 extreme than this soil difference could explain. In fact, it will be 

 noted that plat 6 averaged 10 inches less than check 2, which adjoined 

 it. In the same way, plat 1 averaged 18 inches less than its adjoining 

 check 1. 



A number of photographs were taken to illustrate these differences 

 in height of plants on July 15. Plate I, figure 1, shows a typical 

 plant in plat 1 with the leaves removed, while figure 2 of the same 

 plate shows a typical plant in check plat 2, thus affording a comparison 

 of unshaken plants with those shaken six times a week. To illus- 

 trate this difference further, photographs were made showing the 

 dividing lines between shaken and unshaken cotton. These are 

 given in Plate II. These figures show very well the tremendous 

 effect of the shaking operation on the height and form of the plants. 



In addition to reducing the height, it was found that the sh'akings 

 had considerable influence on the branching and general make-up of 

 the plant. The most frequently shaken plants presented a bushy, 



