Assessment of Entomopathogenic Fungi as Biological Control Agents Against Mosquito Larvae in Kano State, North West Nigeria

This study assesses the biocontrol potential of entomopathogenic fungi against mosquito larvae in natural and simulated breeding habitats in Kano State, located in Nigeria's North West geopolitical zone. Insecticide resistance is increasingly undermining chemical-based vector control programmes in Northern Nigeria, and biological alternatives are urgently needed. Metarhizium anisopliae and Beauveria bassiana isolates recovered from soil samples in Kano, Jigawa, and Katsina States were screened for virulence against third-instar Anopheles gambiae and Culex quinquefasciatus larvae in laboratory bioassays. Dose-response curves were generated and LC50 and LC90 values calculated. The most virulent isolates were evaluated in semi-field conditions using 200-litre tank microcosms simulating natural breeding sites. Efficacy was compared with the conventional larvicide Bacillus thuringiensis israelensis (Bti). Five isolates of Metarhizium anisopliae and three of Beauveria bassiana were evaluated. The most virulent Metarhizium isolate (Kano-Ma3) produced LC50 values of 1.8 x 10^5 conidia/mL for An. gambiae and 2.4 x 10^5 conidia/mL for Cx. quinquefasciatus over 72 hours. Semi-field trials showed 85 percent larval mortality at 1 x 10^7 conidia/mL over five days, comparable to Bti at recommended doses. The study recommends further field evaluation of Kano-Ma3 and development of a locally produced conidial formulation for integration into Kano State's integrated vector management programme. Keywords: entomopathogenic fungi, Metarhizium, biological control, mosquito larvae, Kano State.