3^ 



determined at day 1 to determine carry-over from the pupal stage to the adult 

 and at day 7 upon termination of all tests. Response to treatment was statis- 

 tically significant in reduction of egg production and in reduction of total 

 sterol as compared with appropriate control insects. 



59. Bonham, C. D., and Fye, R. E. 1971. An empirical model for predicting boll 

 weevil distribution on cotton plants. J. Econ. Entomol. 64: 539-540. 



Several sampling schemes can be implemented to determine boll weevil infestation 

 levels in a given field. For example, sampling of contiguous plants and record- 

 ing presence or absence of insects on a given plant would give an estimate of % 

 of plants infested. Sampling (checking of plant for insects) should consider 

 the region of the plant which gives close estimates of the model. For example, 

 the top 6 in. of the plant. Thus, letting NL=estimated number of boll weevils 

 per acre; P=proportion of plants with one or more individuals in percent; N = 

 estimated numbar of boll weevils per infested plant; N =number of plants per 



Si 



acre; X, =number of the 6-in. increment from the top ot the plant where the ob- 

 servations were made (= the i th observation); n.,=number of insects of i th ob- 

 servation; Y.=expected frequency of insects at the j th distance, as obtained 

 from equation 1, we can estimate infestation levels in a given field. If X, is 

 the region of interest and a mean value is used for n (i.e., n) based on a suffi- 

 cient sample, values of Y, and Nu will be close to their true population values. 

 The value of Y given X. is obtained from (3) and N = n/Y,; N, = (N ) (P) (N ) 

 is the estimated infestation level for the field. The estimate is clearly re- 

 lated to the distribution of the insect population on plants throughout the field 

 and should be considered in designing field sampling plans. 



60. Borkovec, A. B. 1975. Chemosterilizatlon of the boll weevil. Chemosteri- 

 lant News (India). 2: 3-8. 



An integrated approach to the containment or elimination of th- boll weevil. 



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