Utilização dos fungos Metarhizium anisopliae e Beauveria bassiana no controle do mosquito Aedes aegypti

Abstract

Aedes aegypti is vector of zika, dengue, urban yellow fever and chikungunya. It is a cosmopolitan mosquito with pronounced adaptive plasticity making it difficult controlling. Metarhizium anisopliae and Beauveria bassiana are entomopathogenic fungi found in the environment parasitizing arthropods and are therefore widely used for agricultural pest control. Researches using fungi, seek to identify more virulent and selective isolates, and develop technologies that provide an efficacy and resistance to environment effects. The aim of study was evaluating and comparing virulence conidia and blastospores using different isolates of M. anisopliae and B. bassiana suspended in water and mineral oil formulation on A. aegypti larvae. Strains CG 153, IBCB 481, ARSEF 2211 of M. anisopliae, CG 206, CG 479 of B. Bassiana were grown in PDA medium (Potato dextrose agar) to producing conidia and Adamek medium modified to producing Blastospores. Larvae (L1/L2) were immersed in 10 mL of sterile dechlorinated water + 0.01% Tween 80 suspensions or oily formulation containing 108 /107 mL-1 conidia and 108 /107 mL-1 blastospores maintained at 27°C and UR > 80%. The survival rates of larvae were evaluated daily for 7 days. In addition, blastospores production capacity among the isolates was evaluated at different time conditions and agitation. The statistical study used was Kaplan-Meier analyzing and comparing the survival rates in relation to treatment time; The parametric data were evaluated by analysis of variance (ANOVA), followed by Turkey test. The calculation of the lethal time (LT50) was performed using the Log-rank test. The level of significance was 5% (p> 0.05%). The strains ARSEF2211, CG479 and CG206 obtained the highest yields of blastospores when maintained at a rotation of 220rpm/72h, whereas strains CG153 and IBCB481 obtained low production. In the biological assays, blastospores and conidia were not statistically significant, and the best results were observed in treatments with 107 conidia/blastospores mL-1 strains CG153, IBCB481; in comparison between suspensions and formulations, they obtained better results than suspensions, with survival rates ranging by 8.56 to 27.44%. The best lethal times (TL50) were obtained in the formulations of blastospores CG479 107 and ARSEF22118 both with 1 day. Therefore, it is concluded that blastospores and conidia showed good control options for A. aegypti and formulations based on mineral oil showed good adjuvant.