Potencial de Bipolaris crotonis como agente de controle biológico do capim-pé-de-galinha (Eleusine indica)

Abstract

Goosegrass (Eleusine indica) is a widely distributed weed in agricultural and forest production systems, characterized by high competitive ability and increasing reports of resistance to chemical herbicides. This scenario has intensified the search for alternative control methods, especially biological control strategies. The present study aimed to evaluate the potential of the fungus Bipolaris crotonis as a biological control agent against E. indica. The fungal isolate was obtained from seeds of the target weed showing disease symptoms, collected in the municipality of Monte Carmelo, Minas Gerais, Brazil. Morphological and molecular analyses were performed to confirm the identity of the isolate. Pathogenicity was assessed through inoculation of mycelial discs onto healthy plants, fulfilling Koch’s postulates. Subsequently, the biocontrol potential of the fungus was evaluated through the application of a conidial suspension produced in a biphasic medium, at a concentration of approximately 1 × 10⁶ conidia mL⁻¹. Inoculated plants showed progressive development of necrotic leaf lesions, ultimately leading to plant death. At the end of the evaluation period, an average control rate of approximately 83% was observed, classified as “good” according to the scale proposed by the Brazilian Society of Weed Science. Additionally, this study represents the first record of Bipolaris crotonis associated with Eleusine indica in Brazil, expanding current knowledge on the geographic distribution of this pathogen. The results indicate that B. crotonis shows promising potential as a bioherbicide and may be incorporated into integrated weed management strategies, contributing to the reduction of reliance on chemical herbicides in agricultural and forest systems.