Background Diaphorina citri Kuwayama is one of the most destructive citrus pests worldwide. It is controlled mainly through applications of conventional insecticides. Methodologies used to estimate resistance to insecticides do not correlate with field efficacy, and do not provide timely and reliable information to make decisions at a site where spraying is needed. The use of diagnostic doses with 30‐min exposure is proposed for estimating the resistance of D. citri to imidacloprid, spinosad, malathion and chlorpyrifos at the orchard level. Results Under laboratory conditions, we estimated the lowest doses that caused 100% mortality within 30 min of exposure (diagnostic dose) in a susceptible D. citri colony. The diagnostic doses for imidacloprid, spinosad, malathion and chlorpyrifos were 7.4, 4.2, 1.0 and 5.5 mg a.i. L−1, respectively. Under field conditions, we applied the diagnostic doses to D. citri feeding on Citrus aurantifolia Swingle at five localities in Michoacan state, Mexico (Nueva Italia, Santo Domingo, El Varal, Gambara and El Ceñidor). Additionally, the field efficacy of these insecticides against these populations was evaluated. A significant correlation between field efficacy and mortality was observed with the diagnostic doses for imidacloprid, malathion and chlorpyrifos (R2 ≥ 0.93). The correlation for spinosad could not be estimated because the mortality caused by the diagnostic dose and its field efficacy at all study sites was consistently >98%. Conclusions Field efficacy and resistance were estimated based on the field diagnostic doses with 30‐min exposure for all tested insecticides. Consequently, growers and pest management technicians can estimate the performance of the evaluated insecticides at the orchard level and before insecticide application. © 2023 Society of Chemical Industry.
Diaphorina citri Kuwayama (Hemiptera: Liviidae) is the most severe pest of citrus worldwide, and it has a high capacity to develop insecticide resistance. We estimated the intraplot variation of resistance to imidacloprid in adults collected from an orchard (8 ha) of Persian lemon, Citrus latifolia Tan., in Martínez de la Torre, Veracruz, Mexico. We divided the orchard into eight sections of similar size. Adults were sampled from each section to assess their response in the F1. We conducted two field samplings: November 2020 and May 2021. The relative response (RR50) at the median lethal mortality (LC50) level in adults collected in the first sampling varied from 518× to 16,701×. Adults collected from Sections 2 and 5 exhibited the highest LC50 values. In the second sampling, adults with the highest LC50 values were collected from Sections 3, 5, and 6. The range of intraorchard variation at the LC50 level (RR50) ranged from 635× to 6,626×. The RR95 values could be estimated in two sections of the first sampling: 7,421× (Section 7) and 58,958× (Section 8). For the remainder of the intraorchard sections in both samplings, the maximum concentration of imidacloprid that could be prepared was 100,000 mg/L, which caused a level of mortality that reached ≤87.9%. The range of variation at the LC50 among sections (FRR50) was low: 1 to 32.17× in the first sampling and 1 to 10.43× in the second. The resistance detected to imidacloprid is the highest recorded worldwide for D. citri.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.