Insecticide resistance in California populations of the glassy‐winged sharpshooter Homalodisca vitripennis

Abstract

BACKGROUND The glassy‐winged sharpshooter, Homalodisca vitripennis (Germar), is a primary vector of Pierce's disease of grapes in California. Systemic imidacloprid treatments have been the mainstay of area‐wide treatment programs that were established in the Central Valley (Kern and Tulare Counties) and Southern California (Riverside County) during the 1990s to combat the pest. The programs helped to suppress populations on citrus, a major sharpshooter host, to levels that significantly reduced migration into adjacent vineyards. However, beginning in 2012, there has been a resurgence of glassy‐winged sharpshooter populations in Kern and Tulare counties, and hitherto successful treatment strategies have not been as effective. This study investigated the possibility that insecticide resistance was a contributing factor to the population resurgence. RESULTS Topical application bioassays detected high levels of resistance to imidacloprid in Kern and Tulare populations, and lower levels of resistance (perhaps due to cross‐resistance) to the foliar neonicotinoid acetamiprid (20‐fold), the pyrethroid fenpropathrin (7.4‐fold), and the butenolide flupyradifurone (4‐fold). Samples of glassy‐winged sharpshooters from citrus groves under organic management also exhibited high levels of imidacloprid resistance. CONCLUSION The long‐term use of imidacloprid has selected for resistance in glassy‐winged sharpshooters. The most resistant populations also exhibited resistance to the foliar neonicotinoid acetamiprid, the pyrethroid fenpropathrin, and the butenolide flupyradifurone. High levels of imidacloprid resistance in insects sampled from organic groves indicate that resistant insects are migrating from nearby conventional groves, which could compromise the control of sharpshooters in organic systems with insecticides affected by cross‐resistance. © 2021 Society of Chemical Industry

Improved draft reference genome for the Glassy-winged Sharpshooter (Homalodisca vitripennis), a vector for Pierce’s disease

“…In August 2019, sharpshooters were collected from citrus groves across multiple locations in California as part of a study on imidacloprid resistance (Byrne and Redak 2021). Of these, three sharpshooters (designated A6, A7, A9) collected from an organic citrus grove (Citrus sinensis (L.) Osbeck) in Porterville, California (Tulare County) were used for genome sequencing.…”

“…Of these, three sharpshooters (designated A6, A7, A9) collected from an organic citrus grove (Citrus sinensis (L.) Osbeck) in Porterville, California (Tulare County) were used for genome sequencing. The insects from this location (Tulare-Organic) were confirmed to be susceptible to imidacloprid using a topical application bioassay (Byrne and Redak 2021).…”

“…Unfortunately, the long-term use of insecticides to control H. vitripennis has led to high levels of resistance in California populations (Byrne and Redak 2021).…”

Metagenome-Assembled Genomes of Bacterial Symbionts Associated with Insecticide-Resistant and -Susceptible Individuals of the Glassy-Winged Sharpshooter (Homalodisca vitripennis)

“…The glassy-winged sharpshooter ( Homalodisca vitripennis ) is an invasive xylem-feeding leafhopper that is native to the southeastern United States and Mexico and was recently introduced into California ( 1 , 2 ). Insecticide-based management of invasive H. vitripennis populations to control for disease transmission has led to high levels of imidacloprid and pyrethroid resistance ( 3 ). Recent studies in other insects have proposed a role for microbes in the resistance mechanisms of hosts ( 4 – 8 ).…”

Efficient CRISPR/Cas9-mediated genome modification of the glassy-winged sharpshooter Homalodisca vitripennis (Germar)

“…Control of GWSS has focused on quarantine restrictions across California, as well as the application of chemical insecticides. Resistance to pyrethroid and neonicotinoid insecticides has emerged indicating that the use of these broad-spectrum insecticides may be short lived 6 , 7 . New approaches for the control of this pest, and other hemipteran pests of agriculture, are urgently needed.…”