44. Cowan, C. B., Jr., Davis, J. W., and 

 Parencia, C. R., Jr. Winter survival of the 

 boll weevil in cotton bolls in central Texas. 

 Jour. Econ. Ent. 56: 494-496. 1963. 



Boll weevils can overwinter in bolls on 

 standing stalks in the fields, and, also, in bolls 

 on the soil surface, even during winters of more 

 than usual severity. When bolls were buried to 

 a depth of 2 inches on December 1, survival 

 occurred even though stalks were destroyed 

 and fields plowed in early winter. Such survival 

 was considerably less than for bolls left on soil 

 surface. Such survival could be important in 

 areas where favorable hibernation sites are 

 scarce or nonexistent. 



45. Cowan, C. B., Jr., Parencia, C. R., Jr., 

 and Davis, J. W. Control of several cotton 

 insects in field experiments in 1960. Jour. 

 Econ. Ent. 54 : 1011-1014. 1961. 



Dusts or sprays of toxaphene plus DDT or 

 Strobane plus DDT were equally effective 

 against the boll weevil and the bollworm. 

 Geigy 30494, or Bayer 29493, Shell SD-5539, 

 and Shell SD-5533 gave fair-to-good control of 

 the boll weevil, but none of these materials 

 were so effective as Guthion. Methyl Trithion 

 plus DDT was ineffective against the cabbage 

 looper when used in a regular schedule of ap- 

 plications against the bollworm and boll weevil. 



46. Cross, W. H., and Mitchell, H. C. 

 Color chart for marking insects. Jour. Econ. 

 Ent. 57: 301. 1964. 



A color chart was developed for use of one 

 to five colors applied on one to five positions on 

 the boll weevil. Individual adults may be 

 marked and their movements studied in the 

 cottonfield. As many as 7,775 weevils may be 

 marked. Copies of a chart prepared for the use 

 of four colors, numbering all 3,124 possible 

 combinations in a systematic sequence, are 

 available. 



47. CURL, L. F. Mexico-United States co- 

 operative plant pest control programs. Jour. 

 Econ. Ent. 57: 450-452. 1964. 



History of the 45 years of cooperative efforts 

 are given with histories of the six insects in 

 the current pest control program. The boll 

 weevil is included. 



48. Davich, T. B., and others. Mass mark- 

 ing boll weevil field populations. Jour. Econ. 

 Ent. 58: 1035-1037. 1965. 



Hardee, D. D., Cleveland, T. C, and Burt, 

 E. C, joint authors. 



A slow-drying, nontoxic blue enamel and 

 other enamels were applied to fields from a 

 spray plane and from a tractor-mounted 

 sprayer. Weevils were collected after to 

 38 days. Tables of percentages and dura- 

 tion of markings are given. It is believed that 

 more than 50 percent of the weevils could be 

 marked if the field were sprayed by plane by 

 the prescribed method. This method may be 

 useful in studies with other insects. 



49. Davich, T. B., and others. Preliminary 

 field experiments with sterile males for eradi- 

 cation of the boll weevil. Jour. Econ. Ent. 58 : 

 127-131. 1965. 



J. C. Keller, E. B. Mitchell, P. Huddleston, 

 R. Hill, D. A. Lindquist, G. McKibben, and 

 W. H. Cross, joint authors. 



During 1962 apholate-sterilized males, nor- 

 mal males, and virgin untreated females were 

 released in two experimental 1-acre plots in 

 Virginia and Tennessee in the ratio of 20:1:1 

 in each of five uniformly distributed points. In 

 seven additional weekly releases, about 20 

 sterile males were placed at each distribution 

 point. Release of the sterile males failed to 

 achieve eradication, possibly because of low 

 competitiveness of the males subject to this 

 sterilant. In a third experimental plot in Loui- 

 siana, 10 gravid females were released and 

 permitted to oviposit for 6 days before the 

 initiation of a sterile-male release program de- 

 signed to provide an overwhelming number of 

 sterile males at the height of the Fi emergence. 

 A total of 8,850 sterile males released over an 

 8-week period prevented or nullified matings 

 between the ensuing F x males and females. 

 Dissection of oviposition-punctured squares, col- 

 lected from the 4th to 11th week after release 

 of sterile males began, failed to yield a larva, 

 pupa, or adult. Proof that eradication was 

 achieved was obtained on the 17th week of the 

 experiment when no egg or feeding punctures 

 were found in two examinations of all the 

 squares and bolls on plants in the field. A high 

 ratio of sterile insects was required to achieve 

 eradication; but the experiment established 

 that the sterility principle could be applied for 

 the elimination of a boll weevil population, 

 even when the sterile males used were low in 

 mating competitiveness. 



50. Davich, T. B., and Lindquist, D. A. 

 Exploratory studies on gamma radiation for 

 the sterilization of the boll weevil. Jour. Econ. 

 Ent. 55: 164-167. 1962. 



Boll weevil adults, pupae, and eggs were 

 exposed to cobalt. 60 Longevity and egg-laying 

 capacity of reproducing weevils were drasti- 

 cally reduced at doses of 5,000 roentgens or 

 higher ; whereas, egg hatch was greatly reduced 

 at doses as low as 2,500 r. Exposure to 10,000 r 

 produced transient sterility of virgin males; 

 15,000 r resulted in permanent sterility. These 

 doses resulted in rapid mortality in both sexes. 

 A ratio of 3.8:1:1 of sterilized males: normal 

 males: normal females did not affect egg-lay- 

 ing or hatch. There was little, if any, effect of 

 age of adults on susceptibility to lethal effects 

 of gamma rays. 



Emergence of adults from prepupae, young 

 pupae, and old pupae exposed to 10,000 r was 

 eliminated, greatly reduced, and unaffected, 

 respectively. However, the lethal effects were 

 carried over because all the adults died within 



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