Management of navel orangeworm (Lepidoptera: Pyralidae) using four commercial mating disruption systems in California almonds

Authors: HAVILAND, DAVID - University Of California - Cooperative Extension Service; RIJAL, JHALENDRA - University Of California; RILL, STEPHANIE - University Of California - Cooperative Extension Service; HIGBEE, BRADLEY - Trece, Inc; GORDON, CHELSEA - University Of California - Cooperative Extension Service; Burks, Charles - Chuck

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2020
Publication Date: 1/5/2021
Citation: Haviland, D.R., Rijal, J.P., Rill, S.M., Higbee, B.S., Gordon, C.A., Burks, C.S. 2021. Management of navel orangeworm (Lepidoptera: Pyralidae) using four commercial mating disruption systems in California almonds. Journal of Economic Entomology. 114(1):238-247. https://doi.org/10.1093/jee/toaa297.
DOI: https://doi.org/10.1093/jee/toaa297

Interpretive Summary: Mating disruption is used as part of a system of integrated management of navel orangeworm (NOW) on around a third of the approximately 1.5 million acres of almonds and pistachios in California; there is thus room for expansion of use of this minimally toxic control technology. Studies have examined implementation and efficacy of individual mating disruption products for navel orangeworm, but studies comparing multiple commercial products and providing a quantitative analysis of costs and benefits of this technology are lacking. A single-year randomized experiment in the southern San Joaquin Valley comparing four NOW mating disruption products with no mating disruption found that mating disruption reduced NOW damage to almonds, and there was no significant difference in damage between the products. A two-year experiment examining adjacent orchards with and without mating disruption and conducted across the San Joaquin Valley provided further confirmation of the value of mating disruption for NOW. An economic analysis of the data from these experiments indicated that mating disruption generally increased net profit for baseline NOW infestation of 0.8 to 1% as assessed from huller samples. These data provide a broader demonstration of the value of mating disruption for NOW and offers guidance on conditions under which it is economically valuable, and will increase adoption of this environmentally soft technology.

Technical Abstract: The navel orangeworm, Amyelois transitella Walker (Lepidoptera: Pyralidae), is the most significant pest of California almonds. Direct feeding on the kernel by the larvae causes reductions in crop yield, quality, and exportability. Mating disruption is a relatively new technique with the potential to improve management. In 2017, we used replicated ~16-ha plots to compare the efficacy of four commercial mating disruption systems (CheckMate®, Cidetrak®, Isomate®, and Semios) for their relative impacts on trap captures and crop quality. From 2017 to 2018, we conducted nine side-by-side studies in 16 to 40 ha almond orchards to compare conventional management programs to programs incorporating mating disruption systems. Across all studies, mating disruption reduced male moth captures in pheromone traps by >94%. In the efficacy study, this led to 35 and 53% reductions in kernel damage in Nonpareil and pollinizer varieties, respectively, and an average increase in crop value of $370 ha-1. In the side-by-side studies, kernel damage to Nonpareil and pollinizer varieties was reduced by 65 and 78%, respectively, resulting in an average increase in crop value of $357 ha-1. Economic analyses showed that increases in crop returns exceeded the costs of implementing mating disruption systems with the break-even point ranging from 0.86 to 1.06% of kernel damage. These results suggest that adding mating disruption to an existing navel orangeworm management program is a cost-effective way to reduce damage while promoting sustainable pest management practices.