Semiochemicals to monitor insect pests-future opportunities for an effective host plant volatile blend to attract navel orangeworm in pistachio orchards

The navel orangeworm (Amyelois transitella) has been a major insect pest of California tree nut orchards for the past five decades. In particular, almond and pistachio orchards suffer major annual economic damage due to physical and associated fungal damage caused by navel orangeworm larvae. Until recently, the only viable option, albeit inconsistent, for monitoring navel orangeworm populations within these orchards has been the use of almond meal in egg traps. Over the past several years a synthetic blend of host plant volatiles, based on various almond emissions, has demonstrated effective attractancy of both male and female navel orangeworm in field trapping studies in almond orchards. However, this attractiveness did not extend into the mid-to late-season in pistachio orchards, thus suggesting either an orchard specificity of the moth or perhaps a temporal component expressed as a change in background odors of the orchard. Using information and approaches learned during the development of the almond host plant volatile blend, research within these ARS laboratories has focused on the volatile emissions from various pistachio matrices to ascertain potential semiochemicals capable of attracting navel orangeworm moths in pistachio orchards. Provided herein is a perspective on the challenges and progress of developing a synthetic host plant volatile blend for an agricultural insect pest that has a diverse range of hosts and has proven difficult to monitor.