Screening of Fungal Strains and Formulations of <i>Metarhizium anisopliae</i> to Control <i>Phyllotreta striolata</i> in Chinese Flowering Cabbage
(1) Background: The cabbage flea beetle (CFB; <i>Phyllotreta striolata</i>) seriously damages the production of Chinese flowering cabbage (CFC; <i>Brassica campestris</i> L. ssp. <i>chinensis</i> var. <i>utilis</i>), which is a key leafy vegetable in S...
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MDPI AG
2023-06-01
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| Series: | Insects |
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| Online Access: | https://www.mdpi.com/2075-4450/14/6/567 |
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| author | Wei Chen Wenjing Yuan Renkun He Xinhua Pu Qiongbo Hu Qunfang Weng |
| author_facet | Wei Chen Wenjing Yuan Renkun He Xinhua Pu Qiongbo Hu Qunfang Weng |
| author_sort | Wei Chen |
| collection | DOAJ |
| description | (1) Background: The cabbage flea beetle (CFB; <i>Phyllotreta striolata</i>) seriously damages the production of Chinese flowering cabbage (CFC; <i>Brassica campestris</i> L. ssp. <i>chinensis</i> var. <i>utilis</i>), which is a key leafy vegetable in South China. A large number of chemical insecticides have been sprayed to control this pest; as a result, residues and resistances are becoming an issue. It is necessary to develop biocontrol technologies to address this issue. (2) Methods: Fungal strains were selected based on bioactivity against CFB, and CFC seed pelletization with fungal conidia was subject to evaluation of control efficacy against CFB. The effective mixture of fungus and chemical insecticide was determined based on safety and joint toxicology tests. (3) Results: The screening of 103 strains from 14 genera identified the <i>Metarhizium anisopliae</i> strain MaGX19S02 (Ma) as the one with the highest virulence. The LC<sub>50</sub>s of Ma to CFB adult and second instar larvae on day 9 post-treatment were 3.04 × 10<sup>6</sup> and 27.2 × 10<sup>6</sup> spores/mL, respectively. In the pot test, the pelletization of CFC seeds with Ma conidia (50/25/12.5 mg in 1 g seed with 4 g fillers) demonstrated significant CFB mortalities (45–82%) 20 days after the larvae were introduced. In the field test, the seed pelletization achieved 57–81% control efficacy 14 days after sowing. Furthermore, the combination of Ma with chlorfenapyr (Chl) demonstrated a synergistic effect against CFB; based on this result, we prepared the mixture formulation of 20% Ma-Chl wettable powder (WP). The assessment of the effects of 20% Ma-Chl WP (500× diluent) against CFB revealed 93.33% mortality in the pot test and 61.3% control efficacy in the field test on day 7 post-treatment. (4) Conclusions: The findings demonstrate the potential of Ma to control CFB in the field. Seed pelletization with Ma conidia effectively controlled CFB larvae and protected CFC seedlings, wherein a mixture formulation of 20% Ma-Chl WP had substantial efficacy in controlling CFB adults. Our research provides new methods for CFB biocontrol. |
| first_indexed | 2024-03-11T02:19:37Z |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-11T02:19:37Z |
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| spelling | doaj.art-a5d956849e7d4feeaaef42f8558bc0122023-11-18T10:56:35ZengMDPI AGInsects2075-44502023-06-0114656710.3390/insects14060567Screening of Fungal Strains and Formulations of <i>Metarhizium anisopliae</i> to Control <i>Phyllotreta striolata</i> in Chinese Flowering CabbageWei Chen0Wenjing Yuan1Renkun He2Xinhua Pu3Qiongbo Hu4Qunfang Weng5National Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou 510642, ChinaNational Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou 510642, ChinaNational Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou 510642, ChinaNational Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou 510642, ChinaNational Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou 510642, ChinaNational Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China(1) Background: The cabbage flea beetle (CFB; <i>Phyllotreta striolata</i>) seriously damages the production of Chinese flowering cabbage (CFC; <i>Brassica campestris</i> L. ssp. <i>chinensis</i> var. <i>utilis</i>), which is a key leafy vegetable in South China. A large number of chemical insecticides have been sprayed to control this pest; as a result, residues and resistances are becoming an issue. It is necessary to develop biocontrol technologies to address this issue. (2) Methods: Fungal strains were selected based on bioactivity against CFB, and CFC seed pelletization with fungal conidia was subject to evaluation of control efficacy against CFB. The effective mixture of fungus and chemical insecticide was determined based on safety and joint toxicology tests. (3) Results: The screening of 103 strains from 14 genera identified the <i>Metarhizium anisopliae</i> strain MaGX19S02 (Ma) as the one with the highest virulence. The LC<sub>50</sub>s of Ma to CFB adult and second instar larvae on day 9 post-treatment were 3.04 × 10<sup>6</sup> and 27.2 × 10<sup>6</sup> spores/mL, respectively. In the pot test, the pelletization of CFC seeds with Ma conidia (50/25/12.5 mg in 1 g seed with 4 g fillers) demonstrated significant CFB mortalities (45–82%) 20 days after the larvae were introduced. In the field test, the seed pelletization achieved 57–81% control efficacy 14 days after sowing. Furthermore, the combination of Ma with chlorfenapyr (Chl) demonstrated a synergistic effect against CFB; based on this result, we prepared the mixture formulation of 20% Ma-Chl wettable powder (WP). The assessment of the effects of 20% Ma-Chl WP (500× diluent) against CFB revealed 93.33% mortality in the pot test and 61.3% control efficacy in the field test on day 7 post-treatment. (4) Conclusions: The findings demonstrate the potential of Ma to control CFB in the field. Seed pelletization with Ma conidia effectively controlled CFB larvae and protected CFC seedlings, wherein a mixture formulation of 20% Ma-Chl WP had substantial efficacy in controlling CFB adults. Our research provides new methods for CFB biocontrol.https://www.mdpi.com/2075-4450/14/6/567<i>Phyllotreta striolata</i><i>Metarhizium anisopliae</i><i>Brassica campestris</i>seed pelletizationmixed insecticide |
| spellingShingle | Wei Chen Wenjing Yuan Renkun He Xinhua Pu Qiongbo Hu Qunfang Weng Screening of Fungal Strains and Formulations of <i>Metarhizium anisopliae</i> to Control <i>Phyllotreta striolata</i> in Chinese Flowering Cabbage Insects <i>Phyllotreta striolata</i> <i>Metarhizium anisopliae</i> <i>Brassica campestris</i> seed pelletization mixed insecticide |
| title | Screening of Fungal Strains and Formulations of <i>Metarhizium anisopliae</i> to Control <i>Phyllotreta striolata</i> in Chinese Flowering Cabbage |
| title_full | Screening of Fungal Strains and Formulations of <i>Metarhizium anisopliae</i> to Control <i>Phyllotreta striolata</i> in Chinese Flowering Cabbage |
| title_fullStr | Screening of Fungal Strains and Formulations of <i>Metarhizium anisopliae</i> to Control <i>Phyllotreta striolata</i> in Chinese Flowering Cabbage |
| title_full_unstemmed | Screening of Fungal Strains and Formulations of <i>Metarhizium anisopliae</i> to Control <i>Phyllotreta striolata</i> in Chinese Flowering Cabbage |
| title_short | Screening of Fungal Strains and Formulations of <i>Metarhizium anisopliae</i> to Control <i>Phyllotreta striolata</i> in Chinese Flowering Cabbage |
| title_sort | screening of fungal strains and formulations of i metarhizium anisopliae i to control i phyllotreta striolata i in chinese flowering cabbage |
| topic | <i>Phyllotreta striolata</i> <i>Metarhizium anisopliae</i> <i>Brassica campestris</i> seed pelletization mixed insecticide |
| url | https://www.mdpi.com/2075-4450/14/6/567 |
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