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Chinese Agricultural Science Bulletin ›› 2025, Vol. 41 ›› Issue (10): 133-140.doi: 10.11924/j.issn.1000-6850.casb2024-0508

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Synergistic Effect of Three Microbial Pesticides Mixed with Chemical Pesticides on Tuta absoluta Eggs and Larvae

WANG Haoling1,2(), ZHU Jiaonan3, CHEN Qi3, DING Jiasheng4, WANG Xibo5, LI Haitian6, ZHANG Kai3, XIE Lixia6, GUO Wenxiu1, WANG Guiping1(), YU Yi1()   

  1. 1 Shandong Key Laboratory for Green Prevention and Control of Agricultural Pests/ Institute of Plant Protection, Shandong Academy of Agricultural Sciences, Jinan 250100
    2 School of Medicine, Qilu Institute of Technology, Jinan 250200
    3 School of Forestry Engineering, Shandong Agricultural Engineering College, Jinan 250100
    4 Dehong Plant Protection and Quarantine Station of Yunnan Province, Dehong, Yunnan 678400
    5 Shandong Weili Seedling Co., Ltd., Jinan 250212
    6 College of Plant Protection, Shandong Agricultural University, Tai’an, Shandong 271018
  • Received:2024-08-12 Revised:2025-02-20 Online:2025-04-05 Published:2025-04-03

Abstract:

To screen out the better agents for controlling the eggs and larvae of Tuta absoluta, the leaf-dipping method was employed to assess the indoor toxicity of 11 agents, as well as the synergistic effects of mixtures of biopesticides and chemical pesticides. The findings revealed the following toxicity rankings of different agents on the eggs of T. absoluta in the laboratory: emamectin benzoate> abamectin> spinetoram> indoxacarb> rotenone> matrine> beta-cypermethrin·emamectin benzoate> azadirachtin> Metarhizium anisopliae CQMa421> Bacillus thuringiensis> Beauveria bassiana ZJU435. Regarding the toxicity to the larvae of T. absoluta, the ranking was: emamectin benzoate> abamectin> spinetoram> matrine> rotenone> beta-cypermethrin·emamectin benzoate> indoxacarb> azadirachtin> Metarhizium anisopliae CQMa421> Beauveria bassiana ZJU435> Bacillus thuringiensis. Metarhizium anisopliae CQMa421, Beauveria bassiana ZJU435, and Bacillus thuringiensis were each blended with emamectin benzoate, spinetoram, and indoxacarb at active-ingredient ratios of 1:9, 3:7, 5:5, 7:3, and 9:1 to evaluate the synergistic effects on the eggs of T. absoluta. When Metarhizium anisopliae CQMa421and indoxacarb were combined at an active-ingredient ratio of 9:1, the co-toxicity coefficient reached its peak at 204.90, demonstrating the most pronounced synergistic effect. The tests indicated that emamectin benzoate, avermectin, and spinetoram exerted high toxicity on both the eggs and larvae of T. absoluta. The mixtures of Metarhizium anisopliae CQMa421, Beauveria bassiana ZJU435, and Bacillus thuringiensis with emamectin benzoate, spinetoram, and indoxacarb manifested synergistic effects, thereby enhancing the control of T. absoluta and reducing the reliance on chemical pesticides.

Key words: Tuta absoluta, biopesticide, chemical pesticide, mixed pesticides, virulence determination, synergistic effect, reduction of chemical agents