Diversidade e distribuição espacial de fungos fitopatogênicos como agentes de controle biológico ao capim pé-de-galinha (Eleusine indica)

Abstract

The goosegrass (Eleusine indica L.) is a weed that competes with agricultural crops and has developed resistance to herbicides with different modes of action. This study was part of the first phase of a biological control program for this target plant. This phase involved the collection of phytopathogenic fungi associated with E. indica. A total of 88 fungal isolates were collected in the states of Minas Gerais, São Paulo, and Goiás, of which 50 demonstrated pathogenicity to goosegrass. Twenty-six isolates were considered more aggressive, belonging to the genera Bipolaris, Fusarium, Curvularia, Exserohilum, and Alternaria, whose occurrence was influenced by climatic factors such as temperature and precipitation. A higher incidence of fungi was observed under conditions of high humidity and temperatures between 20°C and 30°C. Additionally, phylogenetic analyses identified six possible new species of phytopathogenic fungi associated with E. indica, three from the genus Curvularia and three from the genus Bipolaris, highlighting the need for integrated approaches for taxonomic delimitation. Phylogenetic analysis showed that classification based solely on morphological characteristics is insufficient. Furthermore, new morphological characteristics of Curvularia nodulosa were described, with identification confirmed through molecular sequence analyses. The bioprospecting of fungi is essential for the development of effective bio-herbicides and is crucial for subsequent stages aimed at selecting an antagonist for the target species.