1150 



EXPERIMENT STATION RECORD. 



Preliminary report upon experiments with powdered arsenate of lead as 

 a boll weevil poison, W. Xkwki.i, .-md T. (". r.AijriFii (Crop /'(st Coin. Ln. (lire. 

 23. PI). i)--'iO, pi/x. 3). — The authors first present a brief review of the use of 

 Paris green in eombatinj: the boll weevil. At their recjuest one firm attempted 

 and, after some experimentation, succeeded in the spring of liios in producing a 

 powdered arsenate of lead. Plxperiments carried out with this iusecticide are 

 reported in which it was found to be twice as effective as Taris green, and that 

 if applied to cotton just before the tirst squares form 70 per cent of the boll 

 weevils then present would be killed. Conclusions as to the probable profit fol- 

 lowing such application should be drawn with caution, since all the boll weevils 

 are not out of hibernation when the squares first appear. For the destruction 

 of the cotton caterpillar or leaf worm in midsummer, powdered arsenate of lead 

 is preferred to Paris green since it is equally as effective, is noninjurious to the 

 cotton plant, and is cheaper. Powdered arsenate of lead is also considered a 

 better application for the bollworm than is Paris green. 



Destroying- the boll weevils before they enter hibernation, W. Xkwell 

 [Crop I'cxt Com. La. Circ. 2'/, /)/). .'//-.'/8). — Attention is called to the importance 

 of fall destruction of cotton stalks. Early and complete destruction is shown to 

 be a necessary iirecedent to the successful use of powdered arsenate of lead the 

 following spring. 



What constitutes a perfect stand of cotton when fighting the boll weevil? 

 W. Newell {Crop I'cxt Com. La. Circ. 2J, pp. lo). — In sections infested by the 

 boll weevil, cotton bolls are not made after August 15 (and oftentimes none 

 after August 1 ) and therefore each plant requires only enough growing room 

 in which to produce bolls up to the date of maximum infestation, about August 

 15. Having in mind these facts, the author conducted experiments to deter- 

 mine what constitutes a perfect stand, by this being meant the number of 

 plants on any given area which will give the greatest yield i)er acre. A sum- 

 mary of the comparative production of widely spaced and closely spaced cotton 

 is presented in the following table : 



Comparative production of cotton in n:i(le roirs. in narrow roics, and in roics of 



medium tiridth. 



Experiment. 



Mansfield, 1907 



Mansfield, 1908 



Mansnra, 1908 



Bayou Pierre, 1908 



Average yield, all experiments 



Yield of seed cotton per acre. 



Widely 

 spaced. 



Pounds. 

 7?A 



838 

 474 

 380 



607 



Closely 

 spaced. 



Pounds. 



947 



1,344 



627 



636 



Medium 

 distance. 



Pounds. 

 892 

 993 

 392 

 553 



These experiments were conducted on such a variety of soils and under such 

 a variety of conditions that the results are considered trustworthy. 



" From our own experience we are inclined to believe that spacing about as 

 follows will give the maximum yields per acre under ordinary conditions: 



" On poor upland soil, rows .S ft. apart, plants 10 in. apart in the row. On 

 rich upland or good prairie soils, rows 3 ft. apart, plants 12 in. apart in the 

 drill. For worn, or very sandy bottom lands, rows 3* ft. apart, plants 12 in. 

 apart in the drill. On l>ottom lands of medium fertility, well drained, rows 4 

 ft. apart, plants 15 in. apart in the drill." 



