Evaluation of Pathogenicity of Entomopathogenic Oomycetes Lagenidium giganteum and L. ajelloi against Anopheles Mosquito Larvae

Malaria is a mosquito-borne life-threatening parasitic disease of humans and the leading cause of mortality and morbidity in sub-Saharan Africa. Despite the major efforts made towards malaria control, it is facing challenges of development of parasite resistance towards antimalarial drugs coupled wi...

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Main Authors: Mathew Mumo Sila, Fredrick Mutie Musila, Vitalis Wafula Wekesa, Imbahale Susan Sangilu
Format: Article
Language:English
Published: Hindawi Limited 2023-01-01
Series:Psyche: A Journal of Entomology
Online Access:http://dx.doi.org/10.1155/2023/2806034
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author Mathew Mumo Sila
Fredrick Mutie Musila
Vitalis Wafula Wekesa
Imbahale Susan Sangilu
author_facet Mathew Mumo Sila
Fredrick Mutie Musila
Vitalis Wafula Wekesa
Imbahale Susan Sangilu
author_sort Mathew Mumo Sila
collection DOAJ
description Malaria is a mosquito-borne life-threatening parasitic disease of humans and the leading cause of mortality and morbidity in sub-Saharan Africa. Despite the major efforts made towards malaria control, it is facing challenges of development of parasite resistance towards antimalarial drugs coupled with Anopheles vector resistance towards insecticides being used in control. There is, therefore, a need to develop complementary control strategies that are economical and environmentally friendly. Biological control using entomopathogenic fungi against the immature malaria mosquito vectors presents an untapped opportunity. This study sought to isolate and characterize entomopathogenic oomycetes Lagenidium giganteum and L. ajelloi from wild Anopheles larvae from Ahero rice fields in western Kenya and test their pathogenicity against laboratory-reared Anopheles gambiae larvae. Laboratory-reared A. gambiae larvae (3rd and 4th instar) were exposed to five different concentrations of L. giganteum and L. ajelloi zoospores; 1000, 2000, 3000, 4000, and 5000 zoospores/mL, respectively. The larval mortality was recorded after 24, 48, 72, and 96 hours post-exposure, until all larvae were dead. The results obtained showed that L. giganteum was not pathogenic to A. gambiae larvae after 24 and 48 hours post-exposure to all concentrations. Larval mortality was recorded at 72 and 96 hours. There were no significant differences observed in the mortalities p>0.05 from all treatments. No mortalities were observed in deionized water (negative control) whereas 100% mortality was recorded in larvae exposed to Bti (positive control). Probit analysis showed that LC50 after 72 hours and 96 hours was 2.32 × 104 and 3.51 × 103 zoospores/ml, respectively. L. ajelloi caused larval mortalities at all the 5 test concentrations after 24-, 48-, 72- and 96-hours post-exposure with LC50 values of 1.18 × 105, 1.43 × 104, and 6.05 × 102, and 27.08 zoospores/ml, respectively. This study isolated and tested two species of Lagenidium from field collected larvae. Lagenidium ajelloi recorded greater pathogenicity than that of L. giganteum against A. gambiae larvae, making them potential candidates for use in the development of bio-larvicide for the control of Anopheles larvae.
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spelling doaj.art-1e54169643e145ac9b51eeaec06ea8f32023-03-13T11:25:29ZengHindawi LimitedPsyche: A Journal of Entomology1687-74382023-01-01202310.1155/2023/2806034Evaluation of Pathogenicity of Entomopathogenic Oomycetes Lagenidium giganteum and L. ajelloi against Anopheles Mosquito LarvaeMathew Mumo Sila0Fredrick Mutie Musila1Vitalis Wafula Wekesa2Imbahale Susan Sangilu3Department of Applied and Technical BiologyDepartment of Applied and Technical BiologyDudutech IPM LimitedDepartment of Applied and Technical BiologyMalaria is a mosquito-borne life-threatening parasitic disease of humans and the leading cause of mortality and morbidity in sub-Saharan Africa. Despite the major efforts made towards malaria control, it is facing challenges of development of parasite resistance towards antimalarial drugs coupled with Anopheles vector resistance towards insecticides being used in control. There is, therefore, a need to develop complementary control strategies that are economical and environmentally friendly. Biological control using entomopathogenic fungi against the immature malaria mosquito vectors presents an untapped opportunity. This study sought to isolate and characterize entomopathogenic oomycetes Lagenidium giganteum and L. ajelloi from wild Anopheles larvae from Ahero rice fields in western Kenya and test their pathogenicity against laboratory-reared Anopheles gambiae larvae. Laboratory-reared A. gambiae larvae (3rd and 4th instar) were exposed to five different concentrations of L. giganteum and L. ajelloi zoospores; 1000, 2000, 3000, 4000, and 5000 zoospores/mL, respectively. The larval mortality was recorded after 24, 48, 72, and 96 hours post-exposure, until all larvae were dead. The results obtained showed that L. giganteum was not pathogenic to A. gambiae larvae after 24 and 48 hours post-exposure to all concentrations. Larval mortality was recorded at 72 and 96 hours. There were no significant differences observed in the mortalities p>0.05 from all treatments. No mortalities were observed in deionized water (negative control) whereas 100% mortality was recorded in larvae exposed to Bti (positive control). Probit analysis showed that LC50 after 72 hours and 96 hours was 2.32 × 104 and 3.51 × 103 zoospores/ml, respectively. L. ajelloi caused larval mortalities at all the 5 test concentrations after 24-, 48-, 72- and 96-hours post-exposure with LC50 values of 1.18 × 105, 1.43 × 104, and 6.05 × 102, and 27.08 zoospores/ml, respectively. This study isolated and tested two species of Lagenidium from field collected larvae. Lagenidium ajelloi recorded greater pathogenicity than that of L. giganteum against A. gambiae larvae, making them potential candidates for use in the development of bio-larvicide for the control of Anopheles larvae.http://dx.doi.org/10.1155/2023/2806034
spellingShingle Mathew Mumo Sila
Fredrick Mutie Musila
Vitalis Wafula Wekesa
Imbahale Susan Sangilu
Evaluation of Pathogenicity of Entomopathogenic Oomycetes Lagenidium giganteum and L. ajelloi against Anopheles Mosquito Larvae
Psyche: A Journal of Entomology
title Evaluation of Pathogenicity of Entomopathogenic Oomycetes Lagenidium giganteum and L. ajelloi against Anopheles Mosquito Larvae
title_full Evaluation of Pathogenicity of Entomopathogenic Oomycetes Lagenidium giganteum and L. ajelloi against Anopheles Mosquito Larvae
title_fullStr Evaluation of Pathogenicity of Entomopathogenic Oomycetes Lagenidium giganteum and L. ajelloi against Anopheles Mosquito Larvae
title_full_unstemmed Evaluation of Pathogenicity of Entomopathogenic Oomycetes Lagenidium giganteum and L. ajelloi against Anopheles Mosquito Larvae
title_short Evaluation of Pathogenicity of Entomopathogenic Oomycetes Lagenidium giganteum and L. ajelloi against Anopheles Mosquito Larvae
title_sort evaluation of pathogenicity of entomopathogenic oomycetes lagenidium giganteum and l ajelloi against anopheles mosquito larvae
url http://dx.doi.org/10.1155/2023/2806034
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