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CORESTA Meeting, Agronomy/Phytopathology, 2023, Cancun, APPOST 11

Screening of insecticides for controlling Myzus persicae in cigar leaf fields and safety evaluation of Rhynocoris fuscipes

CHEN Dexin(1); XIA Changjian(1); SUN Ranfeng(2); MA Guangxiang(2); DENG Haibin(3); WANG Xinggao(2); SHAO Yu(4)
(1) Haikou Cigar Research Institute of Hainan Branch of CNTC, Haikou, Hainan, China; (2) College of Plant Protection, Hainan University, Haikou, Hainan, China; (3) Guangdong Institute of Tobacco Science, Wujiang, Shaoguan City, Guangdong Province, Guangdong, China; (4) Danzhou Branch of Hainan Tobacco Company, Danzhou City, Hainan, China

In order to identify effective and Rhynocoris fuscipes-friendly aphid control agents in tobacco fields, the toxicity of nine common insecticides to Myzus persicae and R. fuscipes was assessed using the leaf-dip and residual film methods in glass tubes, with a subsequent evaluation of the safety of R. fuscipes. Plot experiments were then conducted in tobacco fields. The results showed the following LC50 values of the nine agents for M. persicae: acetamidine (44.311 mg/L), fludizonitrile (46.696 mg/L), rotenone (71.499 mg/L), eucalyptol (77.538 mg/L), dipropirenol (139.697 mg/L) and pyrazidone (175.142) mg/L), pyrethrin (427.589 mg/L), veratrine (322.856 mg/L), Metarhizium anisopliae CQMa421 (205.921 cfu/mL). The highest and lowest LC50 values for second stage nymphs of R. fuscipes were rotenone (139.596 mg/L) and Metarhizium anisopliae CQMa421 (> 1500 cfu/mL). Combined with the safety coefficient and the toxicity ratio, eucalyptol, Metarhizium anisopliae, acetamiprid, pyrzidone and Metarhizium anisopliae CQMa421 demonstrated effective control on M. persicae with less toxicity to second stage nymphs of R. fuscipes. Field experiments showed that the combination of eucalyptol, pyrzidone and Metarhizium anisopliae CQMa421 with R. fuscipes achieved effective control percentages of 93.14 %, 91.22 % and 91.00 %, respectively, surpassing the efficacy of using eucalyptol or R. fuscipes alone. This combined approach exhibited a favourable control effect on tobacco aphids, thus recommending its practical implementation. The results of this study provided valuable guidance for the control of M. persicae in tobacco fields through the alternating use of R. fuscipes and chemical agents, while establishing a basis for large-scale control of aphid giannis and Noctuidae pests in tobacco fields.