Integrated Biological Control Using a Mixture of Two Entomopathogenic Bacteria, <i>Bacillus thuringiensis</i> and <i>Xenorhabdus hominickii</i>, against <i>Spodoptera exigua</i> and Other Congeners
Insect immunity defends against the virulence of various entomopathogens, including <i>Bacillus thuringiensis</i> (Bt). This study tested a hypothesis that any suppression of immune responses enhances Bt virulence. In a previous study, the entomopathogenic bacterium, <i>Xenorhabdus...
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| Format: | Article |
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MDPI AG
2022-09-01
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| Series: | Insects |
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| Online Access: | https://www.mdpi.com/2075-4450/13/10/860 |
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| author | Md Tafim Hossain Hrithik Youngjin Park Hyemi Park Yonggyun Kim |
| author_facet | Md Tafim Hossain Hrithik Youngjin Park Hyemi Park Yonggyun Kim |
| author_sort | Md Tafim Hossain Hrithik |
| collection | DOAJ |
| description | Insect immunity defends against the virulence of various entomopathogens, including <i>Bacillus thuringiensis</i> (Bt). This study tested a hypothesis that any suppression of immune responses enhances Bt virulence. In a previous study, the entomopathogenic bacterium, <i>Xenorhabdus hominickii</i> (Xh), was shown to produce secondary metabolites to suppress insect immune responses. Indeed, the addition of Xh culture broth (XhE) significantly enhanced the insecticidal activity of Bt against <i>S. exigua</i>. To analyze the virulence enhanced by the addition of Xh metabolites, four bacterial secondary metabolites were individually added to the Bt treatment. Each metabolite significantly enhanced the Bt insecticidal activity, along with significant suppression of the induced immune responses. A bacterial mixture was prepared by adding freeze-dried XhE to Bt spores, and the optimal mixture ratio to kill the insects was determined. The formulated bacterial mixture was applied to <i>S. exigua</i> larvae infesting Welsh onions in a greenhouse and showed enhanced control efficacy compared to Bt alone. The bacterial mixture was also effective in controlling other Spodopteran species such as <i>S. litura</i> and <i>S. frugiperda</i> but not other insect genera or orders. This suggests that Bt+XhE can effectively control <i>Spodoptera</i>-associated pests by suppressing the immune defenses. |
| first_indexed | 2024-03-09T20:03:31Z |
| format | Article |
| id | doaj.art-119cb88e0f854f63b7bcf2e135372821 |
| institution | Directory Open Access Journal |
| issn | 2075-4450 |
| language | English |
| last_indexed | 2024-03-09T20:03:31Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
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| series | Insects |
| spelling | doaj.art-119cb88e0f854f63b7bcf2e1353728212023-11-24T00:37:17ZengMDPI AGInsects2075-44502022-09-01131086010.3390/insects13100860Integrated Biological Control Using a Mixture of Two Entomopathogenic Bacteria, <i>Bacillus thuringiensis</i> and <i>Xenorhabdus hominickii</i>, against <i>Spodoptera exigua</i> and Other CongenersMd Tafim Hossain Hrithik0Youngjin Park1Hyemi Park2Yonggyun Kim3Department of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, KoreaAnimal and Plant Quarantine Agency, 167, Yongjeon-ro, Gimcheon 39660, KoreaAnimal and Plant Quarantine Agency, 167, Yongjeon-ro, Gimcheon 39660, KoreaDepartment of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, KoreaInsect immunity defends against the virulence of various entomopathogens, including <i>Bacillus thuringiensis</i> (Bt). This study tested a hypothesis that any suppression of immune responses enhances Bt virulence. In a previous study, the entomopathogenic bacterium, <i>Xenorhabdus hominickii</i> (Xh), was shown to produce secondary metabolites to suppress insect immune responses. Indeed, the addition of Xh culture broth (XhE) significantly enhanced the insecticidal activity of Bt against <i>S. exigua</i>. To analyze the virulence enhanced by the addition of Xh metabolites, four bacterial secondary metabolites were individually added to the Bt treatment. Each metabolite significantly enhanced the Bt insecticidal activity, along with significant suppression of the induced immune responses. A bacterial mixture was prepared by adding freeze-dried XhE to Bt spores, and the optimal mixture ratio to kill the insects was determined. The formulated bacterial mixture was applied to <i>S. exigua</i> larvae infesting Welsh onions in a greenhouse and showed enhanced control efficacy compared to Bt alone. The bacterial mixture was also effective in controlling other Spodopteran species such as <i>S. litura</i> and <i>S. frugiperda</i> but not other insect genera or orders. This suggests that Bt+XhE can effectively control <i>Spodoptera</i>-associated pests by suppressing the immune defenses.https://www.mdpi.com/2075-4450/13/10/860<i>Bacillus thuringiensis aizawai</i><i>Spodoptera exigua</i><i>Xenorhabdus hominickii</i>secondary metabolitebiological control |
| spellingShingle | Md Tafim Hossain Hrithik Youngjin Park Hyemi Park Yonggyun Kim Integrated Biological Control Using a Mixture of Two Entomopathogenic Bacteria, <i>Bacillus thuringiensis</i> and <i>Xenorhabdus hominickii</i>, against <i>Spodoptera exigua</i> and Other Congeners Insects <i>Bacillus thuringiensis aizawai</i> <i>Spodoptera exigua</i> <i>Xenorhabdus hominickii</i> secondary metabolite biological control |
| title | Integrated Biological Control Using a Mixture of Two Entomopathogenic Bacteria, <i>Bacillus thuringiensis</i> and <i>Xenorhabdus hominickii</i>, against <i>Spodoptera exigua</i> and Other Congeners |
| title_full | Integrated Biological Control Using a Mixture of Two Entomopathogenic Bacteria, <i>Bacillus thuringiensis</i> and <i>Xenorhabdus hominickii</i>, against <i>Spodoptera exigua</i> and Other Congeners |
| title_fullStr | Integrated Biological Control Using a Mixture of Two Entomopathogenic Bacteria, <i>Bacillus thuringiensis</i> and <i>Xenorhabdus hominickii</i>, against <i>Spodoptera exigua</i> and Other Congeners |
| title_full_unstemmed | Integrated Biological Control Using a Mixture of Two Entomopathogenic Bacteria, <i>Bacillus thuringiensis</i> and <i>Xenorhabdus hominickii</i>, against <i>Spodoptera exigua</i> and Other Congeners |
| title_short | Integrated Biological Control Using a Mixture of Two Entomopathogenic Bacteria, <i>Bacillus thuringiensis</i> and <i>Xenorhabdus hominickii</i>, against <i>Spodoptera exigua</i> and Other Congeners |
| title_sort | integrated biological control using a mixture of two entomopathogenic bacteria i bacillus thuringiensis i and i xenorhabdus hominickii i against i spodoptera exigua i and other congeners |
| topic | <i>Bacillus thuringiensis aizawai</i> <i>Spodoptera exigua</i> <i>Xenorhabdus hominickii</i> secondary metabolite biological control |
| url | https://www.mdpi.com/2075-4450/13/10/860 |
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