Submitted to: Western Orchard Pest and Disease Management Conference
Publication Type: Abstract only
Publication Acceptance Date: 12/11/2007
Publication Date: 1/9/2008
Citation: Light, D.M., Beck, J.J., Merrill, G.B., Higbee, B. 2008. Pursuit of a Kairomonal Lure for Navel Orangeworm. Western Orchard Pest and Disease Management Conference. Interpretive Summary:
Technical Abstract: The navel orangeworm (NOW), Amyelois transitella, is the chief moth pest that has historically been associated with the introduction of Aspergillus species and the occurrence of aflatoxin in all tree nuts, almonds, pistachios and walnuts, and also figs. Currently, a season-long dependable monitoring lure is lacking for NOW. Critical life-cycle vulnerabilities of NOW are: 1) feeds only on kernels, can’t feed or penetrate hulls and shells, thus must seek prior openings (hull-shell splits) or prior damage incurred by other attacking, 2) does not diapause, must find and overwinter in residual orchard nuts present on the ground or “mummies” that remain on the tree, and 3) multiple eggs are selectively laid on specific nuts. Female moths discriminate and lay eggs selectively on susceptible nuts, including mummies, prior-damaged nuts, and hull – shell split nuts. We are headspace-collecting and GC-MS analyzing the odors emanating from these specific, vulnerable host resources and performing both laboratory (GC-EAD, flight tunnel) and field bioassays to define - identify the specific attractant volatiles present and formulate an optimal lure. Laboratory experiments have clarified the association of NOW nut damage and “vectoring” with Aspergillus infection and levels of aflatoxin contamination. Neonate larvae carry on their body setae A. flavus spores and readily transport spores to almond kernels, and the number of worm feeding holes is correlated with the amount of aflatoxin accumulated. Thus, NOW larvae do vector A. flavus and their nut-penetrating damage does facilitate aflatoxin accumulation. Further, pursuit of a kairomone-based monitoring lure will improve control and management of NOW and Aspergillus.