Identification of Pistachio Associated Volatiles for the Control of Navel Orangeworm

Goals / Objectives
Many different monitoring methods such as almond meal, synthetic blends of pheromones or host plant volatiles are available and used successfully for monitoring navel orangeworm (NOW) infestation in almond orchards. None of these treatment strategies, however, are effective for use in pistachio orchards for still unknown reasons. Previous studies have shown that traps baited with pistachio mummies caught significantly more NOW females than other types of traps in both almond and pistachio orchards. In this project, we aim to identify new pistachio associated volatiles from pistachio mummies that can be used as effective lures for NOW in pistachio orchards. Project Objectives are: 1) identification of pistachio mummy volatiles that elicit strong electroantenographic (EAG) responses in NOW; 2) test potential individual or volatile blends for NOW attraction in pistachio orchards at different flights; and 3) sample pistachio orchard volatile profiles to determine background interference for pistachio lures. Identification of new volatile blends that attract NOW in pistachio orchards would improve pest monitoring and lead to more effective application of IPM for NOW control.

Project Methods
To achieve the proposed objectives, we will: 1) Identify pistachio mummy volatiles that elicit strong electroantenographic (EAG) responses in NOW to add to our existing collection. We will also collect volatiles from pistachio mummies at different stages of microbial degradation or in ground form; 2) Test individual or blends of volatile candidates in lab bioassays and in pistachio orchards. The volatile candidates that elicited strong responses in EAGs will be tested in a lab-based choice bioassay similar to a Y tube choice test as a small scale simulation to verify NOW attraction. Individual or blends of selected volatiles (sorted by class of similar or dis-similar classes of compounds) will then be tested in trap studies in pistachio orchards. Candidate lures will be field tested throughout the growing season and during the various flights of NOW activity as determined by UC Riverside, our field collaborator; 3) Sample pistachio orchard volatile profiles to determine background interference for pistachio lures. We propose to sample pistachio plant materials and orchard volatiles at different growth, maturation, and NOW flight stages (coinciding with when lures are set) to determine a background volatile profile that can be compared with those in the blends.