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<p>Tea mosquito bug, <i>Helopeltis theivora</i> Waterhouse (Hemiptera: Miridae), is a major pest of tea, <i>Camellia sinensis</i> (L.) O. Kuntze, causing up to 50% yield losses in the North Eastern region of India. The management of this pest is challenging owing to its rapid multiplication and development of resistance to conventional insecticides. Therefore, the present study was made to assess the efficacy of naturally occurring native entomopathogenic fungus (EPF), which was isolated from <i>Archips</i>, a leaf feeder pest of Lac host plant, <i>Flemingia semialata</i>. In vitro efficacy of this EPF against <i>H. theivora</i> confirmed its virulence. Hence, the isolate was further characterized at molecular level by using 18&#xa0;S rDNA primer and identified it as <i>Cordyceps javanica</i> (Gene bank accession number, OM321438). Biological parameters viz., radial growth, conidial load, germination as well as its efficacy were accessed along with four different strains against adult <i>H. theivora</i> at 1 × 10<sup>1</sup> to 1 × 10<sup>9</sup> spore dilutions. Among the strains tested, <i>C. javanica</i> showed the best results at 1 × 10<sup>7</sup>conidia/ml with radial growth (75.33&#xa0;mm), conidial density (8.08 × 10<sup>7</sup>conidia/ml), germination (85.49%) and mortality up to 80% with LT₅₀ (4.049 days) and LC₅₀ (5.21 × 10⁶ conidia/ml). The in-vivo efficacy of this strain was assessed in the Experimental Garden for Plantation Crops, AAU, Jorhat which significantly reduced the infestation of <i>H. theivora</i> to 8.33% at 15 days of spraying, compared to insecticide thiamethoxam 25 WG (6.67%). This finding demonstrates that <i>C. javanica</i>, could play a vital role as microbial agent alternative to chemical insecticides for suppressing <i>H. theivora .</i>population.</p>

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Morphological and molecular characterization of Cordyceps javanica (Frieder. & Bally) Kepler and its in-vitro and in-vivo efficacy against tea mosquito bug, Helopeltis theivora waterhouse

  • 期刊论文

  • 发表日期：

    2026年7月24日

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  • Priya Kaur,
  • Purnima Das,
  • Badal Bhattacharyya,
  • Sudeshna Ray,
  • Manuranjan Gogoi,
  • Ratna Kalita,
  • Robin Chandra Boro,
  • Somnath Roy,
  • Banna Ushasri,
  • Abhilisa Mudoi

摘要

Tea mosquito bug, Helopeltis theivora Waterhouse (Hemiptera: Miridae), is a major pest of tea, Camellia sinensis (L.) O. Kuntze, causing up to 50% yield losses in the North Eastern region of India. The management of this pest is challenging owing to its rapid multiplication and development of resistance to conventional insecticides. Therefore, the present study was made to assess the efficacy of naturally occurring native entomopathogenic fungus (EPF), which was isolated from Archips, a leaf feeder pest of Lac host plant, Flemingia semialata. In vitro efficacy of this EPF against H. theivora confirmed its virulence. Hence, the isolate was further characterized at molecular level by using 18 S rDNA primer and identified it as Cordyceps javanica (Gene bank accession number, OM321438). Biological parameters viz., radial growth, conidial load, germination as well as its efficacy were accessed along with four different strains against adult H. theivora at 1 × 101 to 1 × 109 spore dilutions. Among the strains tested, C. javanica showed the best results at 1 × 107conidia/ml with radial growth (75.33 mm), conidial density (8.08 × 107conidia/ml), germination (85.49%) and mortality up to 80% with LT₅₀ (4.049 days) and LC₅₀ (5.21 × 10⁶ conidia/ml). The in-vivo efficacy of this strain was assessed in the Experimental Garden for Plantation Crops, AAU, Jorhat which significantly reduced the infestation of H. theivora to 8.33% at 15 days of spraying, compared to insecticide thiamethoxam 25 WG (6.67%). This finding demonstrates that C. javanica, could play a vital role as microbial agent alternative to chemical insecticides for suppressing H. theivora .population.