Variation in susceptibility and selection for resistance to imidacloprid and thiamethoxam in Mediterranean populations of Orius laevigatus

Abstract

Imidacloprid and thiamethoxam are neonicotinoids that have been tested in several Orius species, including Orius laevigatus (Fieber) (Hemiptera: Anthocoridae), but not the variability in their effect among Orius populations of a single species. In this study, the variation in susceptibility to imidacloprid and thiamethoxam in 30 Mediterranean wild populations and four commercial populations of O. laevigatus was investigated in the laboratory using a standard dip bioassay method. Lethal concentration values (LC 50 ) and the mortality of adults at the maximum field rate (MFR) were calculated. The range of LC 50 of thiamethoxam was from 0.7 to 5.9 mg l À1 , an 8.4-fold variability, obtaining mortality at MFR (100 mg l À1 ) of >89.1% in all populations. The baseline obtained a value of 2.1 mg l À1 , which is very low compared to the MFR. For imidacloprid, the LC 50 varied from 7.7 to 94.7 mg l À1 (12.3-fold variability). Mortalities at the MFR (150 mg l À1 ) were 57.7-99.2%, that is, more variable than for thiamethoxam. The LC 50 value of the baseline was 48.7 mg l À1 , also low compared to the MFR. This variation was exploited to select two populations resistant to thiamethoxam and imidacloprid, respectively. Artificial selection for on average 40 cycles significantly increased the resistance to thiamethoxam (LC 50 = 149.1 mg l À1 ) and imidacloprid (LC 50 = 309.9 mg l À1 ). Mortalities at the MFR in the thiamethoxam-and imidacloprid-resistant populations were 44.5 and 36.9%, respectively. These results demonstrate that resistance can be enhanced in biocontrol agents by artificial selection under laboratory conditions, starting with populations showing no or very low tolerance. Our neonicotinoid-resistant populations might enhance the wider adoption of biological control by allowing punctual or hotspot applications of neonicotinoids to control several main and secondary pests.

Compatibility of early natural enemy introductions in commercial pepper and tomato greenhouses with repeated pesticide applications

“…Pymetrozine, reported as harmless to O. laevigatus in semifield (van de Veire et al, 2002), can decrease fecundity and nymph hatch of O. armatus (Broughton et al, 2013), and this could have played a role in our results (IOBC 2). Also, the variability in the susceptibility of O. laevigatus to insecticides might be explained by the populations used in each study (Balanza et al, 2019).…”

Next Generation Biological Control: The Need for Integrating Genetics and Evolution

“…skills that allows them to rise to the challenges of improving the efficiency of biological pest control through selective breeding of natural enemies in a broad range of agricultural systems and environmental conditions". This has led to measurable scientific progress (Ras et al, 2017;Lirakis, Dolezal, & Schlötterer, 2018;Stahl et al, 2019cStahl et al, , 2019dStahl, Babendreier, & Haye, 2019b;Stahl et al, 2019a;Stahl, Babendreier, & Haye, 2018;Plouvier & Wajnberg, 2018;Balanza , Mendoza , & Bielza , 2019;Koskinioti et al, 2019;Xia et al, 2019;Leung et al, 2019;Lirakis & Magalhaes, 2019;Paspati et al, 2019;Le Hesran et al, 2019;Ferguson et al, in preparation b, in preparation c) as well as to an increasing awareness of the potential of biocontrol agent breeding among scientists, the biocontrol industry, growers, and the general public. We hope that this review will further stimulate the application of genetic and evolutionary methodology in next generation biological control.…”

Does experimental evolution produce better biological control agents? A critical review of the evidence

“…The vast majority of studies we found selected for insecticide resistance in various biological control agents (Figure 1, Table 1). 40-fold (Roush & Hoy, 1981a;Grafton-Cardwell & Hoy, 1986), 65-fold (Zhu et al, 1996), 71-fold (Balanza et al, 2019) and even several hundred-fold (Croft & Meyer, 1973). The insecticides used include organophosphates (e.g., guthion, dimethoate, chlorpyrifos, and malathion), organochlorines (e.g., DDT and endosulfan), pyrethroids (e.g., permethrin and fenvalerate), carbamates (e.g., carbaryl and methomyl), and neonicotinoids (e.g., imidacloprid, nitenpyram, and thiamethoxam).…”

“…In almost all studies, resistance against the applied insecticide increased, from as low as 1.8-fold (Kostiainen & Hoy, 1994) to ca. 40-fold (Roush & Hoy, 1981a;Grafton-Cardwell & Hoy, 1986), 65-fold (Zhu et al, 1996), 71-fold (Balanza et al, 2019) and even several hundred-fold (Croft & Meyer, 1973). Some studies, however, failed to obtain a response to insecticides in natural enemies (Adams & Cross, 1967;Croft & Meyer, 1973;Schulten et al, 1976;Hoy & Knop, 1979;Markwick, 1986;Hamamura, 1987;Havron et al, 1991;Javier et al, 1991).…”