Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/31/2012
Publication Date: 7/31/2012
Publication URL: dx.doi.org/10.1021/jf302658v
Citation: Beck, J.J., Higbee, B.S., Gee, W.S., Merrill, G.B., Hayashi, J.M., Light, D.M. 2012. Hull split and damaged almond volatiles attract male and female navel orangeworm moths. Journal of Agricultural and Food Chemistry. 60(33):8090-8096. Interpretive Summary: Three blend formulations based on almond volatile emissions underwent field trapping studies in almond orchards to determine their ability to attract navel orangeworm, Amyelois transitella Walker (Lepidoptera: Pyralidae). Navel orangeworm is an insect pest to the tree nut industry of California. The efficacy of the blends and subsequent results were evaluated against almond meal, the current commercial standard used for monitoring female A. transitella. The composition of the blends was based on various almond volatile collections. The five-component Blend A comprised 1-octen-3-ol, ethyl benzoate, methyl salicylate, acetophenone, and racemic (E)-conophthorin. The six-component Blend C included the components listed in Blend A but also contained ethyl palmitate. The most complex Blend B with eight components mimicked that of a host plant source and also included 2-phenylethanol, humulene, and nonanal. Ethyl acetate was used as a solvent with a component concentration of 200 mg/2 ml. The blends were tested over several weeks during the first three flights of A. transitella in commercial almond orchards in the southern Central Valley of California. Blend A demonstrated the most consistent capture rate for adult A. transitella throughout the evaluation period, but unlike almond meal also attracted males.
Technical Abstract: A blend of volatiles derived from the emissions of almonds at hull split and mechanically damaged almonds was compared to almond meal, the current monitoring standard for the insect pest navel orangeworm (NOW). Field trapping studies were performed to determine the blend’s ability to attract adult NOW. The blend comprised racemic 1-octen-3-ol, ethyl benzoate, methyl salicylate, acetophenone, and racemic (E)-conophthorin. Ethyl acetate was used as a solvent with a blend component concentration of 100 mg/mL. The blend attracted both sexes of NOW when tested in five 2-week intervals spanning the first three flights of NOW in commercial almond orchards in the southern Central Valley of California. The blend demonstrated consistently higher capture rates for female NOW throughout the evaluation period, but unlike almond meal it significantly attracted males. Reported is a survey of the major and minor volatiles emitted from almonds at hull split, the key period of vulnerability to NOW infestation. Also reported is the attractancy of a formulated test blend based on the host plant volatile emissions, electroantennographic screening experiments, and field trapping studies. The results of this test blend highlight progress toward a host-plant-based attractant for NOW, a major insect pest of California tree nuts that presently lacks an adequate monitoring tool.