Physiological and Biochemical Responses to Sublethal Concentrations of the Novel Pyropene Insecticide, Afidopyropen, in Whitefly Bemisia tabaci MED (Q Biotype)

Xuan Zhou,Ziyi Zhang,Chuanren Li,Qinghe Zhang,Ran Wang,Huixin Zheng,Jingyu Gong

doi:10.3390/agronomy11112260

Abstract

Bemisia tabaci is a devastating agricultural insect pest worldwide, and B. tabaci MED (formerly biotype ‘Q’) threatens the production of horticultural and economic crops in China as a growing number of cases of insecticide resistance have issued, highlighting the requirement for alternative methods and measures of pest management. In the present work, the toxicities of eight popular chemical agents, including the novel pyropene insecticide afidopyropen, on adults of B. tabaci MED were determined, and then physiological and biochemical responses to sublethal concentrations were confirmed. Among all tested chemical agents, afidopyropen exhibited the highest toxicity to adult whiteflies (LC50: 7.38 mg/L). The sublethal effects of afidopyropen were studied at two sublethal concentrations, LC10 (0.53 mg/L) and LC25 (1.84 mg/L), and LC25 treatment extended the duration of growth stages and reduced viabilities in the stages of nymphal, pseudopupae, and adults. The egg-laying days and eggs laid per female were also decreased significantly, as was hatchability in the LC25 treatment. Metabolic enzyme assays suggested that the sublethal effects of LC25 treatment could be ascribable to enhanced detoxification mediated by glutathione S-transferase. In summary, our findings indicate that afidopyropen can be used as a chemical agent for the management of B. tabaci MED whiteflies.

Highlights

The tobacco whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is a notorious insect pest, which is harmful to horticultural and economic crops and highly invasive across the world, and it has been found to infest over 700 species of plants, primarily feeding in the phloem [1,2]
Considering that most chemical agents could degrade rapidly or gradually after the first-time field applications [26], turning lethal concentrations into sublethal concentrations, we evaluated the sublethal effects of LC25 and LC10 of afidopyropen
We found that the toxicity of afidopyropen was the highest among the eight commonly used insecticides tested against B. tabaci MED, while imidacloprid, thiamethoxam, flupyradifuron, flonicamid, sulfoxaflor, and acetamiprid exhibited moderate to relatively high efficacy, and pymetrozine displayed low toxicity

Summary

Introduction

The tobacco whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is a notorious insect pest, which is harmful to horticultural and economic crops and highly invasive across the world, and it has been found to infest over 700 species of plants, primarily feeding in the phloem [1,2]. B. tabaci MED has been the dominant cryptic species and has become one of the most important agricultural insect pests in China [6,7]. While B. tabaci MED has been controlled in China through the application of insecticides such as neonicotinoids, anthranilic diamides, and butenolide insecticides for several years, a significant drop in the susceptibility to these popular chemical agents in whiteflies has been detected in different parts of China, owing to the development of resistance [7,8,9,10].

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Conclusion