Optimizing the Application Timing and Dosage of Metarhizium brunneum Larvae

• Published in: Journal of medical entomology 2023-03, Vol.60 (2), p.339
• Main Authors: Alkhaibari, A.M, Wood, M.J, Yavasoglu, S.I, Bull, J.C, Butt, T.M
• Format: Article
• Language: English
• Subjects: Biological control; Health aspects; Mosquitoes; Pests; Population biology
• ISSN: 0022-2585
• DOI: 10.1093/jme/tjac186

Aedes aegypti (Diptera: Culicidae) is the principal vector of dengue and other viruses that cause disease among 100 to 400 million people each year. The recent development of widespread insecticidal resistance has led to the rapid development of biological control solutions aimed at larval control. While the efficacy of Metarhizium brunneum has been shown against Aedes larvae, the impact of larval population dynamics will need to be determined to formulate effective control strategies. In this study, larvae were subjected to four concentrations of M. brunneum ([10.sup.5], [10.sup.6], [10.sup.7], [10.sup.8] conidia [ml.sup.-1]). Larvae were found to be susceptible to M. brunneum with dose-dependent efficacy. When constant larval immigration was added as a parameter, peak mortality was consistently found to occur on the fourth day, before a significant reduction in control efficacy linked to a decline in conidial availability within the water column. This suggests that M. brunneum treatments should be applied at a concentration 1 x [10.sup.7] conidia [ml.sup.-1] every four days to effectively control mosquito larvae in the field, regardless of the fungal formulation, water volume, or larval density. Understanding fungal-mosquito dynamics is critical in developing appropriate control programs as it helps optimize the fungal control agent's dose and frequency of application. Key words: Metarhizium brunneum, Aedes aegypti, larvae, dynamics, control