from casein diet. In deletion experiments, 

 threonine, tryptophan, and valine were found 

 to be indispensable for growth. Among sugars 

 tested, fructose and sucrose produced the best 

 growth. Maltose, cellobiose, starch, lactose, and 

 glucose were less effective, and poor develop- 

 ment occurred with mannose, melibiose, galac- 

 tose, and ribose. Larvae died without dietary 

 carbohydrate. Dietary fatty acids or the lack of 

 them had no effect on growth. Magnesium was 

 the only mineral indispensable for proper 

 growth. Insects matured in diets without added 

 sodium, calcium, iron, copper, zinc, manganese, 

 molybdenum, cobalt, and iodine salts. Deficien- 

 cies of potassium and phosphate ions were not 

 studied. The effects of* changes in kinds and 

 concentrations of nutrients are discussed. 



175. Vanderzant, E. S., and Davich, T. B. 

 Artificial diets for the adult boll weevil and 

 techniques for obtaining eggs. Jour. Econ. 

 Ent. 54: 923-928. 1961. 



The boll weevil preferred curved- to flat-sur- 

 faced diets. On a cylindrically shaped diet that 

 was hemispheric at one end, the weevils fed and 

 oviposited as well as on cotton buds. 



Composition of diets, method of preparing 

 cylinders, and a mechanical method of remov- 

 ing eggs are given. 



176. Vanderzant, E. S., Pool, M. C, and 

 Richardson, C. D. The role of ascorbic acid 

 in the nutrition of three cotton insects. Jour. 

 Insect Physiol. 8 : 287-297. 1962. 



Purified diets were used to determine the ef- 

 fect of dietary ascorbic acid on the develop- 

 ment of the boll weevil, the bollworm, and the 

 salt-marsh caterpillar. It was shown that ascor- 

 bic acid is an indispensable nutrient for the 

 growth and development of these three insects 

 when reared under aseptic conditions. Boll wee- 

 vil adults fed on diets deficient in ascorbic acid 

 laid fewer eggs with lower hatch than those 

 that received this vitamin. Larvae from eggs 

 that hatched did not survive beyond the second 

 moult unless ascorbic acid was provided in the 

 larval diet. When ascorbic acid was present in 

 the adult diets, the eggs laid hatched into larvae 

 some of which developed to adults even 

 though their larval diets lacked the vitamin. Of 

 the various stages of the boll weevil that were 

 analysed, the egg contained the largest amount 

 of ascorbic acid. Insects fed on diets deficient 

 in ascorbic acid contained very little ascorbic 

 acid. The bollworm and salt-marsh caterpillar 

 have not been reared previously on purified 

 diets. These two insects did not survive beyond 

 the larval stage when their diets contained no 

 ascorbic acid. 



177. Vanderzant, E. S., and Richardson, 

 C. D. Nutrition of the adult boll weevil: 

 Lipid requirements. Jour. Insect Physiol. 10: 

 267-272. 1964. 



Adult boll weevils reared from a defined diet, 

 fed and oviposited similarly on defined adult 



diets with and without corn oil or fat-soluble 

 vitamins. However, when both corn oil and fat- 

 soluble vitamins were omitted from the adult 

 diet, egg laying was markedly reduced. When 

 adult diets lacked inositol, choline, or choles- 

 terol, oviposition was less than half that ob- 

 tained with the complete diet. Adults reared 

 from larval diets without corn oil had a long 

 preoviposition period and a high mortality. 

 When fed the defined adult diet, they laid about 

 half the number of eggs laid by females reared 

 from a larval diet containing corn oil. Omission 

 from the adult diet of corn oil or both corn oil 

 and fat-soluble vitamins further reduced the 

 number of eggs laid. Corn oil could be partially 

 replaced by polyunsaturated fatty acids. The 

 omission of most lipids and lipogenic factors 

 did not seriously affect egg hatch. However, 

 when adults were fed a diet deficient in choles- 

 terol, not a single egg hatched after the 11th 

 day after their emergence. 



178. Walker, J. K., Jr. Emergence pat- 

 tern of first-generation boll weevils in an iso- 

 lated plot during 1960 and 1961. Jour. Econ. 

 Ent. 55: 795-796. 1962. 



Insecticides might be used more efficiently if 

 the size of population of the Fi generation and 

 the time and duration of emergence could be 

 anticipated. In both years studied, the peak of 

 emergence of the Fi generation occurred about 

 30 days after the first square attained size ac- 

 ceptable for oviposition. Results from both 

 years indicate that insecticides applied on a 

 5-day schedule, initiated automatically 25 days 

 after the appearance of the first squares might 

 have been effective in controlling a high per- 

 centage of the Fi generation. 



Although the infestation of overwintered 

 weevils and the percentage of squares punc- 

 tured were similar in 1960 and 1961, a much 

 greater population of first-generation weevils 

 developed in 1960 even though climatic condi- 

 tions were considered unfavorable for weevil 

 increases. 



179. Walker, J. K., Jr., and Bariola, L. A. 

 Oviposition by virgin overwintered boll weevils. 

 Jour. Econ. Ent. 57: 781-782. 1964. 



Thirty-three virgin overwintered boll wee- 

 vil females deposited about 20 eggs per female 

 during a period of about 26 days. Four of the 

 eggs hatched but the young larvae died shortly 

 thereafter. 



180. Walker, J. K., Jr., and Hanna, R. L. 

 A study of boll weevil populations during 1960. 

 Tex. Agr. Expt. Sta. Prog. Rpt. 2211, 8 pp. 

 1961. 



Populations of boll weevils were studied in 

 five treated and one untreated field near Col- 

 lege Station. Data were recorded from 1 22- 

 acre plots, counting areas within each field. 

 Weevil populations in the untreated field 

 doubled from the overwintered to the first gen- 

 eration and redoubled from the first to the 



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