Comparative Effect of Three Neurotoxic Insecticides With Different Modes of Action on Adult Males and Females of Three Tortricid Moth Pests

Bosch

Gemeno

et al. 2019

Bull. Entomol. Res.

We examined the role of the most important metabolic enzyme families in the detoxification of neurotoxic insecticides on adult males and females from susceptible populations of Cydia pomonella (L.), Grapholita molesta (Busck), and Lobesia botrana (Denis & Schiffermüller). The interaction between the enzyme families – carboxylesterases (EST), glutathione-S-transferases (GST), and polysubstrate monooxygenases (PSMO) – with the insecticides – chlorpyrifos, λ-cyhalothrin, and thiacloprid – was studied. Insect mortality arising from the insecticides, with the application of enzyme inhibitors – S,S,S-tributyl phosphorotrithioate (DEF), diethyl maleate (DEM), and piperonyl butoxide (PBO) – was first determined. The inhibitors' influence on EST, GST, and PSMO activity was quantified. EST and PSMO (the phase-I enzymatic activities) were involved in the insecticide detoxification in the three species for both sexes, highlighting the role of EST, whereas GST (phase-II enzymes) was involved only in G. molesta insecticide detoxification. L. botrana exhibited, in general, the highest level of enzymatic activity, with a significantly higher EST activity compared with the other species. It was the only species with differences in the response between sexes, with higher GST and PSMO activity in females than in males, which can be explained as the lower susceptibility of the females to the tested insecticides. A positive correlation between PSMO activity and the thiacloprid LD50s in the different species-sex groups was observed explaining the species-specific differences in susceptibility to the product reported in a previous study.

Section: Introductionmentioning

confidence: 99%

“…A range of 3-15 concentrations per inhibitor, species and sex, were used. 2 Insecticide LC 50(Navarro-Roldán, et al, 2017).…”

mentioning

confidence: 99%

Enzymatic detoxification strategies for neurotoxic insecticides in adults of three tortricid pests

Bosch

Gemeno

et al. 2019

Bull. Entomol. Res.

“…Percentages of mortality after insecticide treatment (Supplementary Table S2) roughly corresponded with typified dose-mortality curves 25 . Sublethal doses of TIA reduced significantly the percentage of GM and LB taking flight, and the percentage of CP and GM orienting to and contacting with the pheromone source (Fig.…”

Section: Resultsmentioning

confidence: 75%

“…Four lethal concentrations (LC 0.001 , LC 1 , LC 10 and LC 20 ) of TIA insecticide [PESTANAL®, analytical standard, ≈100% (a.i. ), diluted in acetone] were tested following previous dose-mortality calibrations 25 . The concentrations (ng a.i./ µ l) applied to CP, GM, and LB, respectively, were: LC 0.001 (0.61, 4.88 and 32.29), LC 1 (4.24, 15.05 and 164.66), LC 10 (12.04, 27.63 and 396.19) and LC 20 (18.70, 35.68 and 573.40).…”

Section: Methodsmentioning

confidence: 99%

“…We recently found that topical application of the neonicotinoid thiacloprid (TIA) substantially reduced pheromone release behaviour in females of three tortricid moth species [ Cydia pomonella (L.), Grapholita molesta (Busck) and Lobesia botrana (Denis & Schiffermüller); from here on “CP”, “GM” and “LB”, respectively], starting at the lethal concentration LC 0.001 which kills only 10 in 10 6 individuals 25,22 . In the present study, we explore the influence of TIA on male perception of, and response and orientation to sex pheromone.…”

Section: Introductionmentioning

confidence: 91%

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Extremely low neonicotinoid doses alter navigation of pest insects along pheromone plumes

Amat

Bau

et al. 2019

Sci Rep

Self Cite

The prevailing use of neonicotinoids in pest control has adverse effects on non-target organisms, like honeybees. However, relatively few studies have explored the effect of sublethal neonicotinoid levels on olfactory responses of pest insects, and thus their potential impact on semiochemical surveillance and control methods, such as monitoring or mating disruption. We recently reported that sublethal doses of the neonicotinoid thiacloprid (TIA) had dramatic effects on sex pheromone release in three tortricid moth species. We present now effects of TIA on pheromone detection and, for the first time, navigational responses of pest insects to pheromone sources. TIA delayed and reduced the percentage of males responding in the wind tunnel without analogous alteration of electrophysiological antennal responses. During navigation along an odor plume, treated males exhibited markedly slower flights and, in general, described narrower flight tracks, with an increased susceptibility to wind-induced drift. All these effects increased in a dose-dependent manner starting at LC 0.001 - which would kill just 10 out of 10 6 individuals - and revealed an especially pronounced sensitivity in one of the species, Grapholita molesta . Our results suggest that minimal neonicotinoid quantities alter chemical communication, and thus could affect the efficacy of semiochemical pest management methods.

Sublethal Effects of Neonicotinoid Insecticide on Calling Behavior and Pheromone Production of Tortricid Moths

Gemeno

2017

J Chem Ecol

Self Cite

In moths, sexual behavior combines female sex pheromone production and calling behavior. The normal functioning of these periodic events requires an intact nervous system. Neurotoxic insecticide residues in the agroecosystem could impact the normal functioning of pheromone communication through alteration of the nervous system. In this study we assess whether sublethal concentrations of the neonicotinoid insecticide thiacloprid, that competitively modulates nicotinic acetylcholine receptors at the dendrite, affect pheromone production and calling behavior in adults of three economically important tortricid moth pests; Cydia pomonella (L.), Grapholita molesta (Busck), and Lobesia botrana (Denis & Schiffermüller). Thiacloprid significantly reduced the amount of calling in C. pomonella females at LC (a lethal concentration that kills only 1 in 10 individuals), and altered its calling period at LC, and in both cases the effect was dose-dependent. In the other two species the effect was similar but started at higher LCs, and the effect was relatively small in L. botrana. Pheromone production was altered only in C. pomonella, with a reduction of the major compound, codlemone, and one minor component, starting at LC. Since sex pheromones and neonicotinoids are used together in the management of these three species, our results could have implications regarding the interaction between these two pest control methods.