AGGREGATION PHEROMONE FOR THE PEPPER WEEVIL, ANTHONOMUS-EUGENII CANO (COLEOPTERA, CURCULIONIDAE) - IDENTIFICATION AND FIELD ACTIVITY

This study describes the identification of an aggregation pheromone fo r the pepper weevil, Anthonomus eugenii and field trials of a syntheti c pheromone blend. Volatile collections and gas chromatography reveale d the presence of six male-specific compounds. These compounds were id entified using chromatographic and spectral techniques as: (Z)-2-(3,3- dimethylcyclohexylidene)ethanol, (E)-2-(3,3-dimethylcyclohexylidene(et hanol, (Z)-(3,3-dimethylcyclohexylidene)acetaldehyde, (E)-(3,3-dimethy lcyclohexylidene)acetaldehyde, (E)-3,7-dimethyl-2,6-octadienoic acid ( geranic acid), and (E)-3,7-dimethyl-2,6-octadien-1-ol (geraniol). The emission rates of these compounds from feeding males were determined t o be about: 7.2, 4.8. 0.45, 0.30, 2.0, and 0.30 mug/male/day, respecti vely. Sticky traps baited with a synthetic blend of these compounds ca ptured more pepper weevils (both sexes) than did unbaited control trap s or pheromone-baited boll weevil traps. Commercial and laboratory for mulations of the synthetic pheromone were both attractive. However, th e commercial formulation did not release geranic acid property, and ge ranic acid is necessary for full activity. The pheromones of the peppe r weevil and the boll weevil are compared. Improvements for increasing trap efficiency and possible uses for the pepper weevil pheromone are discussed. A convenient method for purifying geranic acid is also des cribed.