Skip to main content
ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #392520
Research Project: Epidemiology, Vector-Host Plant Interactions, and Biology of Vegetable and Cucurbit Viruses

Location: Crop Improvement and Protection Research

Title: Epidemiology and economic impact of Impatiens necrotic spot virus: A resurging pathogen affecting lettuce in the Salinas Valley of California

Author
item Hasegawa, Daniel
item DEL POZO-VALDIVIA, ALEJANDRO - Virginia Polytechnic Institution & State University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/2022
Publication Date: 4/20/2023
Citation: Hasegawa, D.K., Del Pozo-Valdivia, A.I. 2023. Epidemiology and economic impact of Impatiens necrotic spot virus: A resurging pathogen affecting lettuce in the Salinas Valley of California. Plant Disease. 107(4):1192-1201. https://doi.org/10.1094/PDIS-05-22-1248-RE.
DOI: https://doi.org/10.1094/PDIS-05-22-1248-RE

Interpretive Summary: Impatiens necrotic spot virus (INSV) is a thrips-transmitted pathogen that has emerged as one of the lettuce industry’s top concerns on the Central Coast of California. This manuscript characterizes the epidemiology of INSV and thrips in commercial lettuce fields by identifying spatial patterns of virus incidence and vector abundance. The manuscript also describes cost analyses that was conducted to estimate the economic impact of the virus and reports on the widespread incidence of the disease in Monterey County. The studies serve as a foundation for future studies to understand thrips and INSV biology to improve their management in the nation’s most important lettuce growing region.

Technical Abstract: The Orthotospovirus, Impatiens necrotic spot virus (INSV) is a thrips-transmitted pathogen of lettuce that has rapidly emerged as a serious threat to production in the Salinas Valley of Monterey County, California. As a first step towards understanding the resurgence of the virus, we utilized Spatial Analysis by Distance IndicEs (SADIE) to characterize the distribution and progression of INSV outbreaks and thrips infestations in two commercial lettuce fields. In both fields, INSV incidence rapidly increased from 15.86% ± 1.77 to 80.24% ± 2.60 over the course of seven weeks and aggregated at specific edges in both fields as early as three weeks after planting (Ia = 1.63, Pa = 0.0100 and Ia = 1.53, Pa = 0.0300). In one of the fields, thrips populations aggregated in areas that also experienced the most INSV (Ia = 1.2435, Pa = 0.0400, week 3; Ia = 1.4815, Pa < 0.0001, week 6; Ia = 1.5608, Pa < 0.0001, week 9), while in the second field, thrips were distributed randomly, despite the aggregated effects that were observed for INSV incidence. Economic analysis estimated that the virus accounted for nearly $400,000 in losses for the two fields, while stakeholder surveys documented over 750 fields that experienced INSV infection during the 2021 season in Monterey County alone. These studies enhance our knowledge on the epidemiology of thrips and INSV under current lettuce production practices in the Salinas Valley, while elucidating the economic consequences and broader challenges that are associated with managing thrips-transmitted viruses.