Potencial da fibra da algaroba para a produção do fungo entomopatogênico Metarhizium anisopliae var. anisopliae.

Abstract

Metarhizium anisopliae is used as a bio-insecticide in the biocontrol of several agricultural pests. For its use in biocontrol it is necessary to produce large-scale conidia. Conidia are produced in rice and due to the high cost of production, there is interest in finding alternative substrates that guarantee the viability and production of large-scale conidia with low cost. Therefore, our objective was to analyze the potential of the algaroba fiber as an alternative substrate for the conidiogenesis of M. anisopliae and its viability on the cutter ant. For conidiogenesis, 1x108 conidia/mL were inoculated into 30 g of the algaroba fiber and analyzed for 10 days. For viability/pathogenicity analysis, 30 leaf cutting ants were used. The ants were immersed in a suspension of 1x108 conidia/mL. A bioassay was performed with three replicates plus the control group. The algaroba fiber guaranteed the growth and sporulation of M. anisopliae. The conidia produced in the fiber of the algaroba were viable with a percentage of germination around 98.21%. The pathogenicity was confirmed in the cutter ant after adhesion and germination of the conidia on the cuticle surface causing 100% death, except for the control group. After 120 h the total mummification of the ants and new conidia were observed, guaranteeing the perpetuation of the fungus. The algaroba fiber indicated to be an alternative substrate for the production of M. ansiopliae, for use in the biological control of several pest insects, to minimize the ecotoxic damages in animal and vegetal production.