usual dusting at 5-day intervals. The price of the cotton must be high to justify 

 the expense. As a rule, small detached areas cannot be dusted by airplane so 

 profitably as large ones. Detailed information and recommendations are included. 



19Z9 - Marlatt, C. L. Report of the Chief of the Bureau of Entomology and Plant Quar- 

 antine (1928-29) U.S.D.A. p. 39. Washington. 



In connection with the control of the boll weevil, a number of dusting ma- 

 chines have appeared on the market that expel a large quantity of dust and allow 

 it to drift across the field, so that swaths of from 300 to 500 ft. can be treated. 

 Careful tests of such dust clouds showed that a large quantity of dust was wasted 

 owing to an overdosage close to the machine and an irregular, inefficient dosage 

 over the remainder of the area. 



1930 - Sherman, F. Results of airplane dusting in the control of cotton boll worm 

 ( Heliothis obsoleta Fab.). J. Econ. Ent. 23(5):810-81 1 . 



Large-scale airplane dusting operations near College Station, Tex., in 1927, 

 indicated that the boll weevil might be successfully controlled on cotton by use of 

 5 to 6 lbs. of calcium arsenate to the acre. 



1934 - Gaines, R„ C., and D. A. Isely. Machinery for dusting cotton. U. S. D, A. Farmers' 

 B. 1729, 14 p., 10 fig. 



In this bulletin, which supersedes a previous one, brief descriptions are 

 given of various types of machines (showing their adaptability to different re- 

 quirements) for use in the United States in applying calcium arsenate dust to 

 cotton against the boll weevil. The chief advantage that aeroplanes have over 

 ground machinery is that they render possible the treatment of fields immediately 

 after heavy or prolonged rains, when the weevils may be causing serious damage. 

 Experience has proved that their use is not more costly. 



1951 - Miller, H, F., and J. C. Gaines. Size of spray nozzle in relation to cotton insect 



control. Tex. Agr. Expt. Sta. Prog. Rpt. 1312. Jan. 18. 



The tests consisted of 3 treatments: (1) hollow cone nozzle (1.8 gal. per 

 acre), (2) hollow cone nozzle (5.4 gal. per acre), and (3) hollow cone nozzle (13.5 

 gal. per acre). One, 2, and 3 nozzles per row were used on the 1st and 2d, 3d, and 

 4th to 10th applications, respectively. Effective control of the boll weevil and 

 other cotton insects was obtained at each rate, as long as the proper amount of 

 toxaphene and toxaphene-DDT spray was applied. The lower rates were more 

 economical. 



1952 - Fife, L. C., R L. Walker, and C. E. Jernigan. Low volume of spray reduces cost 



of boll weevil control. S. C. Agr. Expt. Sta. Ann. Rpt. 64:92-93. 



As the time and labor required to handle excessive amounts of water make 

 spraying expensive, tests were conducted with emulsion sprays of various insec- 

 ticides to determine the smallest volume of spray per acre required to give ade- 

 quate control of the boll weevil. 



In 1950-51 toxaphene emulsion spray was applied with different sizes of 

 hollow-cone-type nozzles to obtain a range of 1.9 to 11.4 gal. per acre. All treat- 

 ments gave equally effective control of the boll weevil. 



1955 - Smith, H. P., and R. L. Hanna. Effects of the type and arrangement of spray 

 nozzle on the control of the cotton bollworm and boll weevil. Tex. Agr. Expt. 

 Sta. Prog. Rpt. 1752. Feb. 13. 



Tests were conducted during 1952-54 at College Station to determine the 

 best type and arrangement of spray nozzle for applying insecticides for the con- 

 trol of the cotton bollworm and boll weevil. Spray nozzles producing a hollow- 

 cone spray pattern resulted in higher yields than spray nozzles producing a flat 

 fan- shaped spray pattern. Sprayed plots yielded approximately half a bale more 

 cotton per acre than unsprayed plots. One hollow-cone type spray nozzle, spray- 

 ing directly over the row, resulted in yields equal to those from 2 and 3 hollow- 

 cone spray nozzles spraying the top and sides of the drill row of cotton plants. 



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