with special reference to combining this 

 method with conventional method. In U.S. 

 Agr. Res. Serv. ARS 33-98, pp. 26-34. 1964. 



Economic losses caused by the boll weevil 

 and the side effects resulting from the exten- 

 sive use of insecticides in its control have indi- 

 cated the desirability of eliminating the insect. 



Combined fall and spring treatment pro- 

 grams might achieve 99 percent reduction in 

 populations. If during the next three genera- 

 tions, 6 billion sterile males could be released 

 eradication should be achieved with a high 

 safety margin. 



When mass rearing methods for the boll 

 weevil are perfected it should be possible to 

 produce 2 million insects (1 million males) for 

 $5,000 or less. The $30 million necessary for 10 

 million acres of cotton would be less than the 

 cost of insecticides and, theoretically, should 

 be more effective. 



To date fully competitive sterile males have 

 not been produced, but if one-half or one-third 

 competitive sterile males are eventually pro- 

 duced eradication should be possible at a cost 

 of $190 million. This $19 per acre is less than 

 many growers now spend on control. Research 

 effort by scientists to achieve this end seems 

 justified. 



90. LaChance, L. E., and Knipling, E. F. 

 Control of insect populations through genetic 

 manipulations. Ent. Soc. Amer. Ann. 55: 

 515-520. 1962. 



The possibility of using insects with in- 

 herited lethal factors to control their own 

 populations is discussed. Mutant strains of the 

 boll weevil with such characteristics as ina- 

 bility to fly, inability to enter diapause, sus- 

 ceptibility to low temperatures or nutritional 

 or morphological defects in the larval stage 

 that would be lethal in the field but not under 

 rearing conditions in the laboratory might 

 achieve the desired effects. The theoretical re- 

 sults of releasing males carrying recessive 

 lethal genes into a natural population on cotton 

 in the United States are described in detail. 

 This might prove a valuable method of control. 



91. Lafever, H. N., Jenkins, J. N., and 

 Maxwell, F. G. Influence of glanded and 

 glandless cottons on insect preference and de- 

 velopment. Agron. Abs. 1964: 72. 1964. 



Current interest in commercial use of gland- 

 less cotton varieties along with reports of 

 greater insect susceptibility of glandless lines 

 indicated a need for data on insect preference 

 and development on glandless versus glanded 

 lines. Emerging boll weevil adults and boll- 

 worm larvae tended to weigh more when 

 reared on glandless cotton square powder diets 

 and glandless field-collected squares than on 

 corresponding glanded "isogenic" lines. In 

 paired comparisons of water extracts of 

 glanded and glandless "isogenic" lines of cot- 

 ton incorporated in agar plugs, weevils fed 



more on the plugs containing extract from the 

 glanded line of the pair in three of five cases. 

 In nonpaired weevil-feeding tests with seven 

 lines, three glandless lines were significantly 

 lower in feeding stimulation that four glanded 

 lines. More eggs were oviposited by boll wee- 

 vils on two unimproved glandless lines than on 

 the glanded commercial check, but all improved 

 glandless lines were below the check. Oviposi- 

 tion tests comparing glanded lines with gland- 

 less "isogenics" showed no general trend. 



92. Lambremont, E. N. Homogenate res- 

 piration of diapausing and nondiapausing boll 

 weevils. Ent. Soc. Amer. Ann. 54: 313-316. 

 1961. 



Measurements on succinate-fortified homo- 

 genates of both field-collected and labora- 

 tory-reared boll weevils showed that the 

 homogenates of nondiapausing weevils consist- 

 ently took up more oxygen than those of dia- 

 pausing weevils. The difference in respiration 

 rate between these two physiological states was 

 significant at the 1-percent level. A difference 

 at the 5-percent level was noted between the 

 respiration of three cultures. There was no 

 significant difference between the sexes. Homo- 

 genates of weevils in diapause contained approx- 

 imately 20 percent more dry-weight material 

 than those of nondiapausing weevils. 



93. Lambremont, E. N. Enzymes in the 

 boll weevil — I. Dehydrogenases of the brain 

 and related structures. Jour. Insect Physiol. 8: 

 181-190. 1962. 



Dehydrogenases were studied in the brain 

 and the related neural and secretory structures 

 in the boll weevil. A reaction system contain- 

 ing an artificial electron acceptor (tetrazolium 

 salt) was used to detect the activity of the 

 various dehydrogenases. Endogenous dehydro- 

 genase activity measured on freshly dissected 

 tissue was found to produce the characteristic 

 pattern of formazan deposition similar to that 

 produced in the tissues of other organisms 

 incubated in tetrazolium solutions. The endoge- 

 nous activity was inhibited by prior freezing, 

 with the result that the only way in which a 

 reaction could be obtained was by adding a 

 subtrate. Various pathways of intermediary 

 metabolism were studied in thawed tissue. All 

 the Krebs cycle intermediates produced posi- 

 tive reactions. Of seven glycolytic intermedi- 

 ates and end-products, alpha-glycerophosphate 

 was dehydrogenated most actively. Glucose-1 

 phosphate and lactate were reacted upon to a 

 lesser extent; but acetate, ethanol, pyruvate, 

 and glycerol gave doubtful or negative results. 

 Three amino acids (glutamate, proline, and 

 aspartate) and one fatty acid (beta-hydroxy- 

 butyrate) gave positive reactions. There was no 

 reaction with choline or hippurate. The coen- 

 zyme dependence of the dehydrogenases was 

 studied. The reaction with lactate was in- 

 creased by diphosphopyridine nucleotide, that 



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