Pyrethroid resistance in <it>Anopheles gambiae </it>leads to increased susceptibility to the entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana</it>
<p>Abstract</p> <p>Background</p> <p>Entomopathogenic fungi are being investigated as a new mosquito control tool because insecticide resistance is preventing successful mosquito control in many countries, and new methods are required that can target insecticide-resista...
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| Format: | Article |
| Language: | English |
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BMC
2010-06-01
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| Series: | Malaria Journal |
| Online Access: | http://www.malariajournal.com/content/9/1/168 |
| _version_ | 1818753686610903040 |
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| author | Knols Bart GJ Farenhorst Marit Koenraadt Constantianus JM Howard Annabel FV Takken Willem |
| author_facet | Knols Bart GJ Farenhorst Marit Koenraadt Constantianus JM Howard Annabel FV Takken Willem |
| author_sort | Knols Bart GJ |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Entomopathogenic fungi are being investigated as a new mosquito control tool because insecticide resistance is preventing successful mosquito control in many countries, and new methods are required that can target insecticide-resistant malaria vectors. Although laboratory studies have previously examined the effects of entomopathogenic fungi against adult mosquitoes, most application methods used cannot be readily deployed in the field. Because the fungi are biological organisms it is important to test potential field application methods that will not adversely affect them. The two objectives of this study were to investigate any differences in fungal susceptibility between an insecticide-resistant and insecticide-susceptible strain of <it>Anopheles gambiae sensu stricto</it>, and to test a potential field application method with respect to the viability and virulence of two fungal species</p> <p>Methods</p> <p>Pieces of white polyester netting were dipped in <it>Metarhizium anisopliae </it>ICIPE-30 or <it>Beauveria bassiana </it>IMI391510 mineral oil suspensions. These were kept at 27 ± 1°C, 80 ± 10% RH and the viability of the fungal conidia was recorded at different time points. Tube bioassays were used to infect insecticide-resistant (VKPER) and insecticide-susceptible (SKK) strains of <it>An. gambiae s.s</it>., and survival analysis was used to determine effects of mosquito strain, fungus species or time since fungal treatment of the net.</p> <p>Results</p> <p>The resistant VKPER strain was significantly more susceptible to fungal infection than the insecticide-susceptible SKK strain. Furthermore, <it>B. bassiana </it>was significantly more virulent than <it>M. anisopliae </it>for both mosquito strains, although this may be linked to the different viabilities of these fungal species. The viability of both fungal species decreased significantly one day after application onto polyester netting when compared to the viability of conidia remaining in suspension.</p> <p>Conclusions</p> <p>The insecticide-resistant mosquito strain was susceptible to both species of fungus indicating that entomopathogenic fungi can be used in resistance management and integrated vector management programmes to target insecticide-resistant mosquitoes. Although fungal viability significantly decreased when applied to the netting, the effectiveness of the fungal treatment at killing mosquitoes did not significantly deteriorate. Field trials over a longer trial period need to be carried out to verify whether polyester netting is a good candidate for operational use, and to see if wild insecticide-resistant mosquitoes are as susceptible to fungal infection as the VKPER strain.</p> |
| first_indexed | 2024-12-18T05:11:18Z |
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| institution | Directory Open Access Journal |
| issn | 1475-2875 |
| language | English |
| last_indexed | 2024-12-18T05:11:18Z |
| publishDate | 2010-06-01 |
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| spelling | doaj.art-3fd781e0eaff441aaadde35f7fffd6932022-12-21T21:19:53ZengBMCMalaria Journal1475-28752010-06-019116810.1186/1475-2875-9-168Pyrethroid resistance in <it>Anopheles gambiae </it>leads to increased susceptibility to the entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana</it>Knols Bart GJFarenhorst MaritKoenraadt Constantianus JMHoward Annabel FVTakken Willem<p>Abstract</p> <p>Background</p> <p>Entomopathogenic fungi are being investigated as a new mosquito control tool because insecticide resistance is preventing successful mosquito control in many countries, and new methods are required that can target insecticide-resistant malaria vectors. Although laboratory studies have previously examined the effects of entomopathogenic fungi against adult mosquitoes, most application methods used cannot be readily deployed in the field. Because the fungi are biological organisms it is important to test potential field application methods that will not adversely affect them. The two objectives of this study were to investigate any differences in fungal susceptibility between an insecticide-resistant and insecticide-susceptible strain of <it>Anopheles gambiae sensu stricto</it>, and to test a potential field application method with respect to the viability and virulence of two fungal species</p> <p>Methods</p> <p>Pieces of white polyester netting were dipped in <it>Metarhizium anisopliae </it>ICIPE-30 or <it>Beauveria bassiana </it>IMI391510 mineral oil suspensions. These were kept at 27 ± 1°C, 80 ± 10% RH and the viability of the fungal conidia was recorded at different time points. Tube bioassays were used to infect insecticide-resistant (VKPER) and insecticide-susceptible (SKK) strains of <it>An. gambiae s.s</it>., and survival analysis was used to determine effects of mosquito strain, fungus species or time since fungal treatment of the net.</p> <p>Results</p> <p>The resistant VKPER strain was significantly more susceptible to fungal infection than the insecticide-susceptible SKK strain. Furthermore, <it>B. bassiana </it>was significantly more virulent than <it>M. anisopliae </it>for both mosquito strains, although this may be linked to the different viabilities of these fungal species. The viability of both fungal species decreased significantly one day after application onto polyester netting when compared to the viability of conidia remaining in suspension.</p> <p>Conclusions</p> <p>The insecticide-resistant mosquito strain was susceptible to both species of fungus indicating that entomopathogenic fungi can be used in resistance management and integrated vector management programmes to target insecticide-resistant mosquitoes. Although fungal viability significantly decreased when applied to the netting, the effectiveness of the fungal treatment at killing mosquitoes did not significantly deteriorate. Field trials over a longer trial period need to be carried out to verify whether polyester netting is a good candidate for operational use, and to see if wild insecticide-resistant mosquitoes are as susceptible to fungal infection as the VKPER strain.</p>http://www.malariajournal.com/content/9/1/168 |
| spellingShingle | Knols Bart GJ Farenhorst Marit Koenraadt Constantianus JM Howard Annabel FV Takken Willem Pyrethroid resistance in <it>Anopheles gambiae </it>leads to increased susceptibility to the entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana</it> Malaria Journal |
| title | Pyrethroid resistance in <it>Anopheles gambiae </it>leads to increased susceptibility to the entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana</it> |
| title_full | Pyrethroid resistance in <it>Anopheles gambiae </it>leads to increased susceptibility to the entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana</it> |
| title_fullStr | Pyrethroid resistance in <it>Anopheles gambiae </it>leads to increased susceptibility to the entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana</it> |
| title_full_unstemmed | Pyrethroid resistance in <it>Anopheles gambiae </it>leads to increased susceptibility to the entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana</it> |
| title_short | Pyrethroid resistance in <it>Anopheles gambiae </it>leads to increased susceptibility to the entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana</it> |
| title_sort | pyrethroid resistance in it anopheles gambiae it leads to increased susceptibility to the entomopathogenic fungi it metarhizium anisopliae it and it beauveria bassiana it |
| url | http://www.malariajournal.com/content/9/1/168 |
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