Comparison of navel orangeworm adults detected with optical sensors and captured with conventional sticky traps

Authors: Burks, Charles - Chuck

Submitted to: AgriEngineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2022
Publication Date: 6/14/2022
Citation: Burks, C.S. 2022. Comparison of navel orangeworm adults detected with optical sensors and captured with conventional sticky traps. AgriEngineering. 4(2):523-532. https://doi.org/10.3390/agriengineering4020035.
DOI: https://doi.org/10.3390/agriengineering4020035

Interpretive Summary: Monitoring insect pests to inform treatment decisions is a cornerstone of Integrated Pest Management (IPM), and remote monitoring devices using cellular and Internet technology to collect and relay these data is an active area of research. Early commercialization of remote monitoring devices has involved primarily camera traps, but these have disadvantages in that an insect is typically still captured on a glue liner that must be serviced in the field, and a large image file must be uploaded through a typically low-bandwidth signal to a computer server for processing. Pseudoacoustic optical sensors represent an alternate technology in which wing frequency provides the signal obtained with infrared sensors to identify a flying insect pest. The insect does not have to be captured to be identified so a glue liner is unnecessary. A field experiment in pistachios compared detection of navel orangeworm with pseudoacoustic sensors with the number of adults captured in traditional glue-lined sticky traps when both were used with either pheromone lures or one of two alternative attractants. When used with pheromone lures the seasonal profile of detection with the pseudoacoustic dispensers matched the traditional traps well, but seasonal profiles did not match for the two alternative attractants. Since mating disruption is widely used for navel orangeworm, attractants other than sex pheromone are important for monitoring for this pest. The navel orangeworm is a key pest for the California almond, pistachio and walnut industries (worth >$8 billion/year unprocessed). This proof of concept for monitoring navel orangeworm and the poorer results found using the alternative attractants will guide scientists and engineers in further development of pseudoacoustic sensor, and will guide early adapters of this technology in the tree nut industries.

Technical Abstract: Attractants used with sticky traps for monitoring navel orangeworm include artificial pheromone lures, ovipositional bait (ovibait) bags, and phenyl propionate; however, the sticky traps have the disadvantages of potentially becoming ineffective because of full or dirty glue surfaces and of having access to data dependent on increasingly expensive labor. A study comparing detection with a commercially available pseudo-acoustic optical sensor (hereafter, sensor) connected to a server through a cellular gateway found similar naval orangeworm activity profiles between the sensor and pheromone traps, and the timestamps of events in the sensors was consistent with the behavior of navel orangeworm males orienting to pheromone. Sensors used with ovibait detected navel orangeworm activity when no navel orangeworm were captured in sticky traps with ovibait, and the timestamps for this activity were inconsistent with oviposition times for navel orangeworm in previous studies. When phenyl propionate was the attractant, sensors and sticky traps were more highly correlated than for pheromone traps on a micro-level (individual replicates and monitoring intervals), but there was high variation and week-to-week profiles differed. These results indicate that these sensors represent a promising alternative to sticky traps for use with pheromone as an attractant, but more research is needed to develop the use of sensors with other attractants. These results will guide developers and industry in transfer of this promising technology.