56^ teXPERIMENT STATION RECORD. tVol. 43 



of seed cotton per acre, or better than two-thirds of a bale. Here the gain 

 over untreated clieck plats amounted to 273.6 lbs., or an increase of nearly S5 

 per cent over checks, and the net profit was $25.23 per acre. In the 4 lowest- 

 yielding, power-dusted plats, with an average of 361 lbs., or one-fourth bale, 

 the gain over the checks was 160 lbs. or 80 per cent, and the net profit averaged 

 $14.72 per acre. The cost for treatment with highest-yielding cotton averaged 

 $10.35 per acre, while with the low yielding it was $6.08 per acre. In all the 

 power-dusting demonstrations of 1919, with an average yield of three-fifths bale 

 per acre, the dusting increased yields by an average of nearly 40 per cent over 

 the check plats. This rate of increase would pay a small profit, at the average 

 cost of treatment in 1919, on fields yielding .'is low as one-fifth bale per acre. 

 However, until we have the results from many more demonstrations than we 

 have at the present time, we feel that we can not advise dusting generally ex- 

 cept where there is a ' prospect ' of more than one-third bale per acre. 



" The average cost per acre for each application in power dusting was $2.13, 

 while in hand-dusting work it was $1.70, at the prices prevailing for labor and 

 materials in 1919. From four to six applications at weekly intervals were 

 necessary for effective weevil control in most cases. Better results may be 

 possible with shorter intervals. Excessive rainfall interfered seriously with 

 the effectivenees of the earlier applications made in 1919, but did not prevent 

 profitable results from the work of the season as a whole. When weevil con- 

 trol is fairly effective through drought and heat, as in 1918, cotton dusting is 

 not likely to prove sufficiently profitable to justify the expenditure. Dusting is 

 most advisable ordinarily to repress a heavy, threatened infestation 'in pro- 

 ductive cotton." 



The hand-dust gun, gas-engine driven dusters, and the wheel-traction duster, 

 together with a lighting system for night work, are considered. 



Poisoning boll weevils, J. B. Watkins {Farm and Ranch, 39 {1920), No. SO, 

 p. 8). — This paper gives an account of the dusting method now in use in con- 

 trolling the boll weevil and the results of tests conducted in Texas, plats having, 

 been selected in localities extending from Karnes City to Fort AVorth. 



On a plat of 35 acres at Austin where poison was used between June 19 and 

 July 9 there was a decrease in the infestation from 82 to 7 per cent. A decrease 

 in infestation on check plats from 78 to 50 per cent is thought to have been 

 due to the fact that some of the poison drifted from the poisoned plat. At 

 the station at Karnes City there was a reduction from 72 per cent to 4 per ' 

 cent after two applications had been made. At San Marcos there was a reduc- 

 tion from 73 per cent to 29 per cent after two applications which were followed 

 by rain. The poisoned plat was full of blooms and bolls, but where it had not] 

 been poisoned there are few b'.ooms and no bolls. 



In these tests the counting was done by three men in order to eliminate the 

 personal factor. The arsenical was applied with hand dust guns. This is saidj 

 to have given the same effect as a four-row machine, having produced a cloud] 

 of dust that hung in the rows for 30 minutes or more when the weatherj 

 conditions were favorable. 



The cotton boll weevil, F. SnrajtAN {N. C. Agr. Ext. Serv. Circ. 104 {1920), 

 pp. 20, figs. 8). — This is a summary of information on the cotton boll weevil, 

 including the history of its invasion of North Carolina, means for combatinf 

 it, etc. 



A new tropical weevil from Florida and Cuba, H. S. Barber {Proc. Ent. 

 Soe. Wash., 22 {1920), No. 6, pp. 150-152, pi. i).— Under the name Metamasius 

 mosieri the author describes a new species collected on Paradise Key, Fla., 

 and Santa Clara Province, Cuba, which is supposed to breed in certain epiphytal ' 

 plants of the tree tops in the jungle-like " hammocks." 



