Screening of Fungal Strains and Formulations of Metarhizium anisopliae to Control Phyllotreta striolata in Chinese Flowering Cabbage

作者：Wei Chen, Wenjing Yuan, Renkun He, Xinhua Pu, Qiongbo Hu, Qunfang Weng · 发表于：Insects · 年份：2023 · DOI：10.3390/insects14060567 · 被引用次数：8 · 研究领域：Entomopathogenic Microorganisms in Pest Control、Insect Resistance and Genetics、Insect Pest Control Strategies

(1) Background: The cabbage flea beetle (CFB; Phyllotreta striolata) seriously damages the production of Chinese flowering cabbage (CFC; Brassica campestris L. ssp. chinensis var. utilis), 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 Metarhizium anisopliae strain MaGX19S02 (Ma) as the one with the highest virulence. The LC50s of Ma to CFB adult and second instar larvae on day 9 post-treatment were 3.04 × 106 and 27.2 × 106 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...