Caracterização e avaliação de sensibilidade a fungicidas e ao herbicida glifosato em isolados de Colletotrichum associados à plantas daninhas

Abstract

Weeds can act as alternative hosts for several pathogens, including fungi of the genus Colletotrichum. In the crop fields, the use of chemical products, whether fungicides or herbicides, is quite high, mainly in the control of weeds, which can act as a source of inoculants of disease- causing pathogens in cultivated plants. Due to lack of information on pathogens associated with weeds in northeastern of Brazil, the present study aimed to characterize and identify the main species of Colletotrichum associated with three different plant species: Euphorbia hirta, Spigelia anthelmia and Sida sp. And check the components of adaptability and sensitivity to three fungicides and the herbicide glyphosate. In the first chapter, the identification and characterization of species of the C. gloeosporioides complex associated with S. anthelmia and the sensitivity of the isolates to three fungicides were carried out: tebuconazol, difenoconazol and a mixture of tebuconazol with trifloxystrobin, in four different dosages, as well as the herbicide. glyphosate. Six species were identified through morphocultural and multilocus phylogenetic analyzes using the genes DNA lyase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), tubulin and the ApMat region: C. fragariae, C. fructicola, C. queenslandicum, C. siamense and C theobromicola. All species were pathogenic to the host and the three fungicides showed varying degrees of inhibition of mycelial growth, with diphenoconazole being the most efficient. The herbicide glyphosate did not present any inhibitory effect for the species evaluated. This being the first report of these species causing anthracnose in S. anthelmia. The second chapter identified and characterized C. truncatum causing anthracnose in three weed species. The identification and characterization was performed through morphocultural analysis and multilocus phylogeny from the GAPDH, actin and ITS region, this being the first report of C. truncatum causing anthracnose in S. anthelmia, Sida and E. hirta. Keywords: Sensibility to Fungicides; Multilocus Analysis; Glyphosate