254 JOURNAL OF ECONOMIC ENTOMOLOGY " [Vol. 3 



each eajre. The phints in two cages were poisoned while those in the other 

 two were not. Four days after the introduction of the weevils on July 30, 

 fully half of them were killed on the poisoned plants, the most of them dying 

 during the first two day^. Altho the effect was not as pronounced as where 

 the weevils were feeding upon squares only, it was so encouraging as to 

 lead up to the extensive experiments of 1909. 



In 1909 experiments were carried on at four different points on a total of 

 95 acres with 12 different plots treated and corresponding check plots. The 

 plots were arranged so as to determine the relative value of from 1 to 10 ap- 

 plications and from 1 to 50 pounds per acre according to the number of times 

 applied. The plots were well laid out to determine these points by compari- 

 son with the checks and the number of infested squares on a considerable 

 number of plants in each plot was counted nine times at weekly or ten day 

 intervals. In determining the profit the cost of the poison and the labor was 

 deducted from the benefit derived in each plot. The average production of 

 all the cotton poisoned in 12 plots on 46 acres was 673.8 pounds per acre. 

 The average production on 12 similar plots not treated, a total of 49 acres, 

 was 392.0 pounds per acre; thus the average increase in production was. 

 281.2 pounds per acre or 71 per cent. The tables show the profits on each 

 plot in detail and the profits are so uniform and the benefit on the whole 

 area is so evident as to exclude any possibility of the results not being thoroly 

 reliable. The greatest profit per acre was secured by dusting five times, 

 which showed a profit of $23.54 per acre. 



Mr. Newell points out that the fall destruction of cotton stalks is neces- 

 sary even with this treatment. If the poison kills 75 per cent, and the weevils 

 be excessively abundant, the 25 per cent not killed would be more than 

 enough to destroy all the squares. This is evidenced by an experiment at 

 Woodside, La., where there was an unusually heavy infestation in 1908 and 

 no cotton was grown in 1909 except on four acres specially planted for the 

 experiment, upon which the weevils were concentrated, there being 5 to 8 

 weevils per plant at the first poisoning. Were it not for the poison the crop 

 would have been totally destroyed. As it was the weevils kept coming in 

 until about July 5 and not until three weeks later or after four applications 

 of the poison, were any squares formed. The most successful experiments 

 with the use of dry arsenate of lead were where the stalks had been destroyed 

 the previous fall and the number of hibernating weevils had been so re- 

 duced that but a small number escaped the poisoning. 



As might be expected the experiments indicated that early varieties show 

 more benefit and it seems probable that the poisoning will be more profitable 

 on the limbless type of cotton than on the spreading sorts, due to the smaller 

 area necessary to dust. Fertilizers also aid in producing earliness with a 

 corresponding greater benefit from the dusting. The applications in the ex- 

 periments wei'e made at weekly intervals, but the experiments do not show 

 just how often the dusting can be made to best advantage. This needs fur- 

 ther work and other points in the practical use of the poison will need to 

 be determined by experiment as the method of application will probably vary 

 with the season and various conditions. 



Mr. Ed Neuwirth at West Monroe, La., secured the best results of several 

 planters who made a practical test of the dry arsenate of lead, securing 1461 

 pounds of seed cotton per acre where it was dusted and 827 pounds per acre 

 on that not dusted, giving an increase of 634 pounds per acre or 76 per 

 cent. He used 6 lbs. of poison per acre, giving four applications. The authors 



