Submitted to: Hawaiian Entomological Society Proceedings
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/12/2011
Publication Date: 12/9/2011
Citation: Mcquate, G.T. 2011. Weathering rate of male sex pheromone of Sweetpotato Weevil, Cylas formicarius elegantulus (Coleoptera: Brentidae), in East Hawaii. Hawaiian Entomological Society Proceedings. 43:1-7. Interpretive Summary: In recent years, sweet potato production in Hawaii has been increasing. Sweet potato production in Hawaii is hindered by three major quarantine pests: the sweetpotato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Brentidae), the West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae) and the sweet potato vine borer, Omphisa anastomosalis (Guenee). It is common practice among sweet potato growers in East Hawaii to harvest the high quality roots and leave the damaged, undersized, or misshapen cull roots in the field. To prevent build-up of pest populations, fields are typically not re-planted again to sweet potato for three years. While sufficient land has been available to permit this type of rotation, if sweet potato production continues to increase, there may be pressure to shorten fallow or rotation periods between successive sweet potato crops and effective pest control methods will be needed. A sex pheromone, (Z)-3-dodecen-1-ol (E)-2-butenoate, has been identified and deployed elsewhere for monitoring and suppression of sweetpotato weevil field populations. As a preliminary step in the development of improved integrated pest management (IPM) methods for sweet potato pests in Hawaii, the longevity of this commercially available sex pheromone attractant for sweetpotato weevil was tested under environmental conditions found in Hawaiian sweet potato fields. Based on the assessment of weathering rates in sweet potato fields on the Hamakua Coast in Hawaii, it was concluded that lures in traps should be replaced every 9 weeks to maintain at least 50% of maximum trap catch. Further research is needed to integrate pheromone-baited traps for sweetpotato weevil into a pest management system for sweet potato pests in Hawaii.
Technical Abstract: In recent years, sweet potato, Ipomoea batatas (L.) Lamarck, production in Hawaii has been increasing, reaching 190 harvested ha, with a total production of 3.78 million kg in 2009. Sweet potato production in Hawaii is hindered by three major quarantine pests, for which only one, the sweetpotato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Brentidae), has an identified sex pheromone, (Z)-3-dodecen-1-ol (E)-2-butenoate, that has been deployed in traps for monitoring and suppression of field populations. The longevity of a commercial source of this sex attractant was tested under field conditions on the Hamakua Coast on the island of Hawaii. Based on a linear regression developed from weevil catch results versus weeks of aging, catch dropped to 50% of the catch of unweathered lure at 13.2 weeks, at a lower elevation site, and at 9.0 weeks, at a higher elevation, windier site. Based on these results, lures in traps should be replaced every 9 weeks to maintain at least 50% of maximum trap catch. Further research is needed to integrate pheromone-baited traps for sweetpotato weevil into a pest management system for sweet potato pests in Hawaii. Suppression of sweetpotato weevil populations may be enhanced by increasing pheromone concentration in traps.