A49 



would provide social benefits of $332 million more than an eradication program. 

 Thus, with this magnitude of difference between social benefits for IPM and 

 eradication, very serious questions as to the economic feasibility of boll 

 weevil eradication must be acknowledged. These results suggest that the 

 estimates of change in yields and costs for the different boll weevil control 

 strategies would have to be grossly inaccurate to change the basic solution 

 and thus the recommendation to this report. 



880. Temple, C, Jr.; Roberts, E. C; Frye, J.; Struck, R. F.; Shealy, Y. F.; 

 Thompson, A. C; Minyard, J. P.; and Hedin, P. A. 1968. Constituents of 

 the cotton bud. XIII. Further studies on a nonpolar feeding stimulant for 

 ■ the boll weevil. J. Econ. Entomol. 61: 1388-1393. 

 The nonpolar feeding stimulant complex for Anthonomus grandis Boheman found in 

 the buds of cotton, Gossypium hirsutum L. (Deltapine Smooth Leaf), was frac- 

 tionated and concentrated. Active fractions were extracted from buds and freeze- 

 dehydrated bud powder with petroleum ether, chloroform, acetone, and chloroform- 

 methanol. These fractions possessed widely different properties from those of 

 the polar fractions studied previously. Silicic acid column chromatography pro- 

 duced a series of related compounds having the properties of the polar lipids. 

 Thin-layer chromatography and countercurrent distribution studies produced com- 

 pounds that were probably pheophytins. When pheophytins a and b were isolated 

 from the bud, they gave high feeding activity after significant purification. 

 Pheophytin a from spinach also gave modest activity, but cotton pheophytin a 

 was inactive after hydrolysis and resterif ication with phytol. These and pre- 

 vious studies of the polar feeding-stimulant complex suggest that a multicomponent 

 system is responsible for optimum feeding activity of the boll weevil. 



