Abstract
Thousands of entomopathogenic fungi are in existence, unexploited and it is important to identify and use for biocontrol of mosquito larva. The aim of this study was to determine the larvicidal efficacy of newly identified entomopathogenic fungi. Soil samples were taken from three different locations in a farmland at Osun State University (UNIOSUN),Osogbo, Nigeria for isolation and identification of entomopathogenic fungi and test its larvicidal effect on mosquito larvae. The samples were analyzed using spread plate technique which include serial dilution of samples, inoculation on prepared Saboraud Dextrose Agar using three dilutions (10-1, 10-3, 10-10) and incubation at 270c for 72 hours after which the plates were examined for growth followed by sub-culturing. Mosquito larvae were breeded, picked into sterile distilled water in Petri dishes. The spores of the fungi were scraped on the larva to determine the larvicidal effect of the fungal isolates at varied interval: 40 minutes, 2 hours, 24hours, and 48hours. A total of seven fungi were isolated two (Aspegillus flavus and Aspergillus niger) of which were able to show larvicidal effect on mosquito larvae. Some larvae died at exactly 40 minutes of inoculation when tested with Aspergillus niger, some took hours (48hours) while others remain viable. This study concludes that Aspergillus niger and Aspergillus flavus isolated from soil samples exhibited biolarvicidal efficacy against mosquito larvae and the mortality rate increases with time of exposure. Entomopathogenic fungi should therefore be explored for control of mosquitoes in our environment.
References
- Odalo J,Omolo M, Malebo H, Angira J, Njeru P, Ndiege I. Repellance of essential oil of some plants from Kenya Coast against Anopheles gambiae. Acta Tropica 2005; 95: 210-18.
- World Health Organization (WHO), (2013). Global Programme to eliminate lymphatic filariasis. (Available on www.who.int).
- Arivoli S., Ravindran J.K., Tennyson S., (2012). Larvicidal Efficacy of plant Extracts against the malaria vector Anopheles stephensis Liston (Diptera:Culicidae).World J. MedSci 7:77-80.
- Bhan S, Shrankhla, Mohan L, Srivasstava CN. Larvicidal toxicity of Temephos and entomopathogenic fungus, Aspergillus flavusand their synergistic activity against malaria vector, Anopheles stephensi. Journal of Entomology and Zoology Studies 2013; 1 (6): 55-60.
- Watarabe T. Pictorial Atlas of soil and seed fungi morphologies of cultured fungi 2010; P295-296.
- Scolte EJ, Knols BGJK, Samson RA,Takken W. Entomopathogenic fungi for Mosquito control: A review.Journal Insect Science 2004; 4:19.
- Augustyniuk-Kram A, Kram K J, Lo JA. Entomopathogenic Fungi as an Important Natural Regulator of Insect Outbreaks in Forests (Review). Forest ecosystem- more than Just Trees 2012; P265-94. (Available on www.intechopen.com).
- Soni N, Soam P. Effect of Chrysosporium keratinoplulum metabolites against Culex quinquefasciantus after chromatographic purification. Parasitol Res 2010; 107: 1329-36 .
- Bukhari T, Willem T. Development of Metarhizium anisopliae and Beauveria bassiana formulations for control of malaria Mosquito larvae. Parasites & Vectors 2011; 4(1):23. DOI: 10.1186/1756-3305-4-23.
- Ellis D, Davis S, Alexiou H, Handke R, Bartley R. Descriptions of medical fungi. 2nd ed. Adelaide, South Australia; 2007.
- Morris SC, Nicholls PJ. An evaluation of optical density to estimate fungal spore concentrations in water suspensions. Phytopathology 1978; 68: 1240-42.
- World Health Organization. (2005). Guidelines for laboratory and field testing of mosquito larvicides. World Health Organization. https://apps.who.int/iris/handle/10665/69101
- Kerwin JL, Washino RK. Field evaluation of Lagenidium giganteum (Oomycetes :Lagendales) and description of a natural epizootic involving a new isolates of fungus. Med. Entomol 1988; 25: 452-60.
- Scolte EJ, Takken W, Knols BGJ. Pathogenicity of five East Africa entomopathogenic fungi to Adult Anopheles gambiae (Diptera: culicidae). Exper. Appl. Entomol. Nev Amsterdam 2003; 1425-9.
- Vyas N, Dua KK, Prakash S. Efficacy of Lagenidium giganteum metabolites on mosquito larvae with reference to non-target organism. Res 2007; 101: 385-90.
- Kerwin JL, Washino RK. Ground and aerial application of the asexual stage of Coelomomyces giganteum for control ofmosquitoes associated with rice culture in the central valley of California. Journal of the American Mosquito Control Association 1987; 3: 59-64.
- Maurya P, Mohan L, Sharma P, Srivastava CN. Evaluation of larvicidal potential of certain insect pathogenic fungi extracts against Anopheles stephensi and Culex quinquefasciatus. Entomological Research 2011; 41(5): 211-15.
- Govindraja M, Jebamesan A, Reetha D. Larvicidal effect of extracellular secondary metabolites of different fungi against the mosquito, Culex quinquesfasciatus. Tropical Biomedicine 2005; 22: 1-3.
Corresponding Author
Adeyemi Temitayo Adeyemo
Department of Medical Microbiology and Parasitology, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria