Abstract
The nonpolar feeding stimulant complex for Anthonomus Grandis Boheman found in the buds of cotton, Gossypium hirsutum L. (Deltapine Smooth Leaf), was fractionated 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 produced a series of related compounds having the properties of the polar lipids. Thin-layer chromatography and countercurrent distribution studies produced compounds 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 reesterification with phytol. These and previous studies of the polar feeding-stimulant complex suggest that a multicomponent system is responsible for optimum feeding activity of the boll weevil.
Published Version
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