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<p>The fall armyworm (FAW), <i>Spodoptera frugiperda</i> (J.E. Smith), is a major invasive agricultural insect pest in Liberia, causing severe yield losses in staple crops, particularly maize, and posing a significant threat to national food security. This research examined the effectiveness of bioextracts and possible antagonistic bacterial isolates in managing FAW in maize. This study evaluated six treatment concentrations of a combined neem (<i>Azadirachta indica</i>) and moringa (<i>Moringa oleifera</i>) bio-extract against FAW. The treatments were defined as follows: T1 (10 mL bio-extract containing 20&#xa0;mg extract in 90 mL distilled water), T2 (8 mL:40&#xa0;mg in 92 mL distilled water), T3 (6 mL:60&#xa0;mg in 94 mL distilled water), T4 (4 mL:80&#xa0;mg in 96 mL distilled water), T5 (2 mL:100&#xa0;mg in 98 mL distilled water), and T6 (control; distilled water only). The combinations of these treatments consistently exhibited the highest mortality rates during the larval, pupal, and adult stages of development. The rates were from 82.27% to 86.3%, 14.56% to 15.14%, and 6.63% to 6.78%, respectively. The results indicated substantial (<i>p</i> &lt; 0.001) disparities in their efficacy against FAW. Additionally, 89 bacterial isolates were isolated from maize tissues, with 35 isolates demonstrating significant biocontrol capabilities through the production of extracellular hydrolytic enzymes and inhibition. ARDRA and BOX analyses on isolates were employed, exhibiting high assessment scores with significant biocontrol efficacy against FAW, preliminarily. Four distinct bacterial strains were identified that exhibited a biocontrol efficacy exceeding 50%. In the greenhouse testing, the biocontrol strains <i>Pantoea sp.</i> (HS-8), <i>Bacillus cereus</i> (DS-26 and DL-7), and <i>Enterobacter sp</i>. (HL-22) demonstrated favorable outcomes. The assessment scores of the 35 biocontrol strains exhibit a correlation coefficient of 0.95, while the biocontrol efficacy against FAW and the antagonist test reveal a correlation coefficient of 0.72. Consequently, the greenhouse and field tests validate the control-efficiency assessment systems, thereby recognizing that the bio-extracts and bacterial isolates may serve as a sustainable pest-control option suitable for integration into agricultural practices.</p>

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Evaluation of bio extracts and potential antagonistic bacterial isolates to control fall armyworm (Spodoptera frugiperda) on Maize

  • 期刊论文

  • 发表日期：

    2026年3月25日

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  • David P. Tokpah,
  • Ovgu Isbilen,
  • Abraham Mahari

摘要

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is a major invasive agricultural insect pest in Liberia, causing severe yield losses in staple crops, particularly maize, and posing a significant threat to national food security. This research examined the effectiveness of bioextracts and possible antagonistic bacterial isolates in managing FAW in maize. This study evaluated six treatment concentrations of a combined neem (Azadirachta indica) and moringa (Moringa oleifera) bio-extract against FAW. The treatments were defined as follows: T1 (10 mL bio-extract containing 20 mg extract in 90 mL distilled water), T2 (8 mL:40 mg in 92 mL distilled water), T3 (6 mL:60 mg in 94 mL distilled water), T4 (4 mL:80 mg in 96 mL distilled water), T5 (2 mL:100 mg in 98 mL distilled water), and T6 (control; distilled water only). The combinations of these treatments consistently exhibited the highest mortality rates during the larval, pupal, and adult stages of development. The rates were from 82.27% to 86.3%, 14.56% to 15.14%, and 6.63% to 6.78%, respectively. The results indicated substantial (p < 0.001) disparities in their efficacy against FAW. Additionally, 89 bacterial isolates were isolated from maize tissues, with 35 isolates demonstrating significant biocontrol capabilities through the production of extracellular hydrolytic enzymes and inhibition. ARDRA and BOX analyses on isolates were employed, exhibiting high assessment scores with significant biocontrol efficacy against FAW, preliminarily. Four distinct bacterial strains were identified that exhibited a biocontrol efficacy exceeding 50%. In the greenhouse testing, the biocontrol strains Pantoea sp. (HS-8), Bacillus cereus (DS-26 and DL-7), and Enterobacter sp. (HL-22) demonstrated favorable outcomes. The assessment scores of the 35 biocontrol strains exhibit a correlation coefficient of 0.95, while the biocontrol efficacy against FAW and the antagonist test reveal a correlation coefficient of 0.72. Consequently, the greenhouse and field tests validate the control-efficiency assessment systems, thereby recognizing that the bio-extracts and bacterial isolates may serve as a sustainable pest-control option suitable for integration into agricultural practices.