1958 - Wessling, W„ H. Genotypic reactions to boll weevil attack in upland cotton. 

 J. Econ. Ent. 51(4):508-512. 



Mutant lines of Upland cotton carrying any 2 of 4 mutant genes--Hn , H2, 

 gl, and R\, --which promised to confer a certain degree of resistance to attack 

 by boll weevil, were tested together with lines having the same genetic back- 

 ground but differing by opposite alleles to the genes under test. All mutant lines 

 showed varying degrees of resistance to boll weevil attack; the lines combining 

 Hi and H2 to the highest degree, those combining gl and H2, and gl and H^, rank- 

 ing second and third. Lines carrying the genes Rj in combination with gl or H2 

 were tested in a separate experiment. Both strains showed a relatively high de- 

 gree of resistance. The main effects of the mutant genes Hj, H^, and gl, could 

 only be estimated on the assumption that their interactions were unimportant. 

 On this basis the data obtained in the experiments indicate that H2 contributed 

 more to resistance than H^ while gl had no significant effect. 



1958 - Wessling, W. H. Resistance to boll weevil in mixed populations of resistant and 

 susceptible cotton plants. J. Econ. Ent. 51(4):502-506. 



The reliability of resistance to attack by the boll weevil, conferred by the 

 mutant gene, H2, was tested under different environmental conditions; that is, 

 in different proportions of the mutant strain, Pilose, and the susceptible variety, 

 All- In- One, or in the absence of susceptible plants. 



In order to carry out this test it was necessary to isolate individual plots 

 from one another, using corn as a barrier crop, and to provide a uniform infesta- 

 tion of boll weevils. This method proved satisfactory. The degree of resistance 

 was measured inversely by the proportion of squares with egg-laying punctures. 

 The mutant strain, Pilose, showed a significantly lower proportion of egg-laying 

 punctures throughout the investigation. A slight but consistent increase in num- 

 ber of egg-laying punctures, with increase in the number of susceptible plants in 

 the mixture, was noted in the resistant strain, Pilose, as well as in the sus- 

 ceptible variety, All- In- One. 



CONTROL - EQUIPMENT 



1920 - Johnson, E„, and B. R. Coad. Dusting machinery for cotton boll weevil control. 



U. S. D. A. Farmers' B. 1098, 31 p. Jan. 



Considered only as a progress report, and issued solely for the purpose of 

 recording the information on the dusting machinery that has been secured up to 

 1920. The special factors governing the construction of the cotton-dusting ma- 

 chine include the type of labor available, the areas to be treated in the field, 

 field conditions, the necessity for night operation, the characteristics of poison 

 utilized, and the type of dust cloud required. The recommendations given in this 

 paper are not, however, considered in any way final, and it is expected that im- 

 provements will be developed from time to time for years to come. 



1921 - Coad, B. R. Killing boll weevils with poison dust. U. S. D. A. Ybk 1920-21:241- 



252, 2 fig. 



Details of suitable machinery for dusting. 



1924 - Coad, B. R„, E. Johnson, and G. L. McNeil. Dusting cotton from aeroplanes. 

 U. S. D. A. Dept. B. 1204, 40 p., 19 fig. 



A method of releasing insecticide dust from aeroplanes was adapted in tests 

 against Alabama argillacea Hb. and, to a certain extent, against Anthonomus 

 grandis. The tests described did not, by any means, determine the practicability 

 of using this means of applying insecticides, but they showed that the dust can be 

 blown onto plants from the air and can be made to adhere to the plants under 

 daytime conditions. Alabama argillacea was successfully controlled with much 

 less poison than is necessary with ordinary dusting machines, and, though a more 

 thorough application would be necessary to control A. grandis , indications are 



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