6 BULLETIN 731, U. S. DEPARTMENT OF AGRICULTURE. 



EXPERIMENTS IN 1917. 



EXPERIMENTS AT TALLULAH, LA. 



At the beginning of the season of 1917 it was recognized that the 

 experiments to date had merely demonstrated the possibility of 

 poisoning weevils successfully, and that all phases of the economic 

 use of the poison remained still to be worked out. Consequently a 

 very elaborate series of experiments was inaugurated in that season, 

 and about seventy-five tests were started in the neighborhood of 

 Tallulah, each one intended to determine some particular point of 

 importance. These consisted of studies of the comparative efficacy of 

 different poisons, the time of day of application giving the best results, 



Fig. 3, 



-Typical view of opened cotton in poisoned plat on Algodon Cut No. 2, second picking, October 12, 

 1916, Tallulah, La. For comparison with figure 4. 



the most profitable season of application, the proper interval between 

 applications, the requisite amount of poison per acre, and many 

 other similar questions, all of which would have to be answered before 

 definite general advice as to the use of the poison could be given. 

 The early studies had shown that under certain conditions poisoning 

 was profitable, but it was apparent that any change in these con- 

 ditions might easily result in a much lower gain, if not in an actual 

 loss, and it was essential to determine thoroughly the possibilities 

 and limitations of boll-weevil poisoning before releasing any informa- 

 tion for public use. Unfortunately for the experimental work, the 

 season of 1017 in the vicinity of Tallulah was most remarkable for 

 the light degree of weevil damage. This was due to a poculiar com- 



