ARS | Publication request: Developing ambient almond orchard volatile mixtures for navel orangeworm (NOW) monitoring

Submitted to: Almond Board of California
Publication Type: Abstract Only
Publication Acceptance Date: October 16, 2009
Publication Date: December 9, 2009
Citation: Beck, J.J., Higbee, B.S., Light, D.M., Dragull, K.D., Merrill, G.B., Gee, W.S. 2009. Developing ambient almond orchard volatile mixtures for navel orangeworm (NOW) monitoring. Almond Board of California.

Interpretive Summary: The navel orangeworm (NOW) continues to be one of the most harmful insect pests to almonds. In 2002, one of the twelve top research priorities in the almond industry included “develop…more refined monitoring systems for NOW” and “study methods to improve pheromone mating disruption techniques and cost effectiveness for NOW…” Additionally, one of the top educational priorities for the almond industry as “new pest management tools as they become available”. Statements and plans such as these underscore the need to address the problems associated with NOW for almonds. Research on attractants for NOW monitoring and lure and trap purposes has not yet yielded a commercially viable and dependable product. In the laboratory setting, NOW puff (a volatile sample passed across the insect) or electroantennogram (EAG) studies typically utilize laboratory ambient air as the background volatile. This presents the problem that ambient laboratory air is not providing an appropriate bouquet of VOCs that would normally be perceived by the NOW in an almond orchard environment. Consequently, any potential VOC puff the NOW receives from researchers may not elicit an appropriate response due to the absence of typical “orchard” volatiles, thus researchers may be missing key signals from NOW. Although the non-quantified VOC make-up of almond orchards has been reported, and the VOC composition of removed almonds has been investigated, the specific, quantified, ambient almond orchard VOC composition has not been investigated. This research will provide current and future NOW bioassay investigations with a quantified analysis of ambient almond orchard volatiles, thus offering a realistic VOC composition as the background effluent to test potential NOW attractants.

Technical Abstract: The navel orangeworm (NOW) continues to be a major insect pest of California tree nuts. There is twofold interest in controlling NOW, namely its direct damage to tree nuts and the associated contamination with toxin-producing fungi resulting from NOW feeding damage. Current efforts to monitor NOW utilize virgin female NOW traps or almond meal, both of which are beneficial but have proven either unavailable commercially or inadequate, respectively. The pheromone blend, while a promising attractant, is hampered by stability problems in the field. Recent work with both ambient and in situ volatile organic compounds (VOCs) from almonds has provided a bouquet of plant-derived volatile compounds as background signaling volatiles (BSVs).