Scholarlink

<p>The sweetpotato weevil, <i>Cylas formicarius</i> (Fabricius, 1798) (Coleoptera: Brentidae), is a serious pest of sweet potatoes, damaging crops in the field and &#xa0;during&#xa0;storage. Its cryptic nature limits chemical control. Entomopathogenic fungi (EPF) like <i>Metarhizium anisopliae</i> sensu lato (s.l.) (Metschnikoff) Sorokin, 1883 (Ascomycota: Hypocreales) offer eco-friendly alternatives. This study aimed to isolate and characterize a native <i>M. anisopliae</i> s.l. strain from infected <i>C. formicarius</i> using morphological and molecular methods and to evaluate its biocontrol potential against the weevil under in vitro conditions. Morphological characteristics and molecular analyses were used to confirm the identity of the isolate. Virulence was tested at three spore concentrations and compared with the commercial <i>M</i>. <i>anisopliae</i> s.l. strain ARSEF5369. Scanning electron microscopy (SEM) was employed to visualize the infection process. Enzyme activities (chitinase, protease) were quantified to compare virulence between strains. The effects of culture media and temperature on fungal growth and sporulation were investigated to optimize mass production conditions. The native isolate caused higher adult mortality (96.7, 93.3, and 50%) than the commercial strain at 1.2 × 10<sup>8</sup>, 5.5 × 10<sup>7</sup>, and 6.2 × 10<sup>6</sup> conidia/mL after 7&#xa0;days. The median lethal concentrations 30 (LC<sub>30</sub>) and LC<sub>50</sub> of <i>M. anisopliae</i> s.l. strain Pm04 against <i>C. formicarius</i> were 2.15 × 10<sup>7</sup> and 3.7 × 10<sup>7</sup> conidia/mL, respectively, while at 1.2 × 10<sup>8</sup> conidia/mL, the lethal times 30 (LT<sub>30</sub>) and LT<sub>50</sub> were 2.33 and 2.4&#xa0;days. Fungal infection stages were evident under SEM,&#xa0;and native strain exhibited elevated enzymatic activities relative to the commercial strain. Optimal growth and spore yield occurred at 25 ± 1°C on sabouraud dextrose agar (SDA)&#xa0;medium. These results highlight the potential of the native <i>M. anisopliae</i> s.l. strain as a promising biocontrol agent against <i>C. formicarius</i>, warranting further evaluation under field conditions.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Pathogenicity of the Entomopathogenic Fungus Metarhizium anisopliae s.l. (Ascomycota: Hypocreales) Against Sweetpotato Weevil (Cylas formicarius, Coleoptera: Brentidae) Under In Vitro Conditions

  • 期刊论文

  • 发表日期：

    2025年11月13日

查看全文
  • Muhammad Riaz,
  • Tsui-Ying Chang,
  • Lekhnath Kafle,
  • Wen-Hua Chen

摘要

The sweetpotato weevil, Cylas formicarius (Fabricius, 1798) (Coleoptera: Brentidae), is a serious pest of sweet potatoes, damaging crops in the field and  during storage. Its cryptic nature limits chemical control. Entomopathogenic fungi (EPF) like Metarhizium anisopliae sensu lato (s.l.) (Metschnikoff) Sorokin, 1883 (Ascomycota: Hypocreales) offer eco-friendly alternatives. This study aimed to isolate and characterize a native M. anisopliae s.l. strain from infected C. formicarius using morphological and molecular methods and to evaluate its biocontrol potential against the weevil under in vitro conditions. Morphological characteristics and molecular analyses were used to confirm the identity of the isolate. Virulence was tested at three spore concentrations and compared with the commercial M. anisopliae s.l. strain ARSEF5369. Scanning electron microscopy (SEM) was employed to visualize the infection process. Enzyme activities (chitinase, protease) were quantified to compare virulence between strains. The effects of culture media and temperature on fungal growth and sporulation were investigated to optimize mass production conditions. The native isolate caused higher adult mortality (96.7, 93.3, and 50%) than the commercial strain at 1.2 × 108, 5.5 × 107, and 6.2 × 106 conidia/mL after 7 days. The median lethal concentrations 30 (LC30) and LC50 of M. anisopliae s.l. strain Pm04 against C. formicarius were 2.15 × 107 and 3.7 × 107 conidia/mL, respectively, while at 1.2 × 108 conidia/mL, the lethal times 30 (LT30) and LT50 were 2.33 and 2.4 days. Fungal infection stages were evident under SEM, and native strain exhibited elevated enzymatic activities relative to the commercial strain. Optimal growth and spore yield occurred at 25 ± 1°C on sabouraud dextrose agar (SDA) medium. These results highlight the potential of the native M. anisopliae s.l. strain as a promising biocontrol agent against C. formicarius, warranting further evaluation under field conditions.