Monitoring persistence of the entomopathogenic fungus Metarhizium anisopliae under simulated field conditions with the aim of controlling adult Aedes aegypti (Diptera: Culicidae)

Abstract

BackgroundEntomopathogenic fungi are potential candidates for use in integrated vector management, with recent emphasis aimed at developing adult mosquito control methods. Here we investigated the persistence of the fungus Metarhizium anisopliae when tested against female A. aegypti under field conditions.MethodsBlack cotton cloths impregnated with M. anisopliae conidia, formulated in vegetable oil + isoparaffin, were maintained on a covered veranda for up to 30 days. At specific times, pieces of the cloths were removed, placed in Tween 80 and the resuspended conidia were sprayed directly onto mosquitoes. The persistence of conidia impregnated on black cloths using three different carriers was evaluated in test rooms. Fifty mosquitoes were released into each room and after a 5 day period, the surviving insects were captured. Another 50 insects were then released into each room. The capacity of the fungus at reducing mosquito survival was evaluated over a total of 35 days.ResultsConidia extracted from cloths maintained on the veranda for 2 to 18 days remained virulent, with 28 to 60% mosquito survival observed. Mosquito survival following exposure to fungus impregnated cloths showed that fungus + Tween caused similar reductions to that of fungus + vegetable oil. Mosquitoes exposed to the formulation fungus + vegetable oil had survival rates of 36% over the first 5 days of the experiment. Following the release of the second cohort of mosquitoes (6-11days), survival increased to 50%. The survival of the 12–17 day cohort (78%) was statistically equal to that of the controls (84%). Formulation of the fungus in vegetable oil + isoparaffin increased the persistence of the fungus, with the 18–23 day cohort (64% survival) still showing statistical differences to that of the controls (87% survival).ConclusionsThe potential of entomopathogenic fungi for the control of adult A. aegypti was confirmed under field conditions. Vegetable oil + isoparaffin formulations of M. anisopliae significantly increased the effectiveness of the fungus, thus reducing the need for frequent changes of black cloths in residences. Our future aim is to obtain effective control of mosquito populations, with cloths only needing to being replaced once a month.

Entomopathogenic organisms: conceptual advances and real-world applications for mosquito biological control

“…We have shown this method to be effective under field simulation conditions, significantly reducing the survival times of female A. aegypti. 38 We initially tested fungus-impregnated black cotton cloths hung in large cages into which female A. aegypti had been released. The survival curves of control and fungus-treated insects were significantly different.…”

Aedes aegypti Pupae are Highly Susceptible to Infection by Metarhizium anisopliae Blastospores

“…A more comprehensive option for insect control is the use of entomopathogenic fungi. M. anisopliae is highly promising for the control of A. aegypti, as this fungus infects eggs, larvae and adults 9,10,11 .…”

O Uso De Jogos Pedagógicos No Ensino De Microbiologia

“…Trabalho realizado por Gomes et al (2015) demonstrou a virulência do óleo vegetal de Nim (Azadirachta indica) contra larvas de A. aegypti. Fungos entomopatogênicos também são eficientes no controle de larvas (PEREIRA et al, 2009) e mosquitos adultos (CAROLINO et al, 2014;PAULA et al, 2008) da espécie A. aegypti.…”