CONSTITUENTS OF COTTON BUD COMPOUNDS ATTRACTIVE TO BOLL WEEVIL

Essential oil from buds of the cotton plant (Gossypium hirsutum L. CV Deltapine Smoothleaf) was fractionated by several procedures. Mixtures and single compounds thus obtained were bioassayed for plant attractancy to the boll weevil, Anthonomus granais Boheman. Compounds present in cotton and active as components of the plant attractant complex are (-)-α-pinene, (-)-limonene, (-)-β-caryophyllene, (+)-β-bisabolol (a sesquiterpene alcohol reported only in cotton thus far), caryophyllene oxide, and two as yet unidentified sesquiterpenoids. The boll weevil-cotton plant attractant complex thus appears to be a mixture of many compounds. An aqueous mixture of 10, 3, 100. 100, and 30 p.p.b., respectively, of commercial (+)-α-pinene and (+)-limonene, cotton bud oil (-)-β-caryophyllene and (+)-β-bisabolol, and synthetic caryophyllene oxide from cotton (-)-β-caryophyllene, is 124% as attractive in laboratory assays as the best available attractant mixture from cotton buds. This synthetic mixture remains highly attractive to boll weevils at concentrations 30-fold higher and 10-fold lower. © 1969, American Chemical Society. All rights reserved.