AUTHOR=Li Shuang , Xu Chaomin , Du Guilin , Wang Guangjun , Tu Xiongbing , Zhang Zehua 

TITLE=Synergy in Efficacy of Artemisia sieversiana Crude Extract and Metarhizium anisopliae on Resistant Oedaleus asiaticus

JOURNAL=Frontiers in Physiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.642893

DOI=10.3389/fphys.2021.642893

ISSN=1664-042X

ABSTRACT=<p>In order to explore the synergistic control effect of crude extracts of <italic>Artemisia sieversiana</italic> and <italic>Metarhizium anisopliae</italic> on <italic>Oedaleus asiaticus</italic>, we used different doses of <italic>M. anisopliae</italic> and crude extracts of <italic>A. sieversiana</italic> singly and in combination, to determine their toxicities to fourth instar <italic>O. asiaticus</italic>. The results showed that the combination of 10% crude extract of <italic>A. sieversiana</italic> with 10<sup>7</sup> and 10<sup>8</sup> spores/g <italic>M. anisopliae</italic> concentrations and the combination of 20% crude extract of <italic>A. sieversiana</italic> with 10<sup>7</sup> and 10<sup>8</sup> spores/g <italic>M. anisopliae</italic> concentrations had significant effects on the mortality, body weight gain, body length gain, growth rate, and overall performance of <italic>O. asiaticus</italic> than those of the crude extract of <italic>A. sieversiana</italic> and <italic>M. anisopliae</italic> alone. Among them, the 20% <italic>A. sieversiana</italic> crude extract mixed with 10<sup>8</sup> spores/g <italic>M. anisopliae</italic> and 10% <italic>A. sieversiana</italic> crude extract combined with 10<sup>7</sup> spores/g <italic>M. anisopliae</italic>, had the best control efficacy. In order to clarify the biochemical mechanism underlying the immune responses of <italic>O. asiaticus</italic> to the pesticide treatments, we monitored the activities of four enzymes: superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT), and polyphenol oxidase (PPO). The results showed that the activities of three enzymes (SOD, CAT, and PPO) were significantly increased from the treatment with the combination of <italic>M. anisopliae</italic> mixed with crude extract of <italic>A. sieversiana</italic>. Interestingly, compared to the crude extract, the combination treatment did not significantly induce the expression of POD enzyme activity, which may be a biochemical factor for increasing the control effect of the combination treatment. Our results showed that the combination treatment had synergistic and antagonistic effects on host mortality, growth, development, and enzyme activities in <italic>O. asiaticus</italic>.</p>