Abstract

Aims This study investigated the diversity ofColletotrichumisolates recovered fromConyza bonariensisleaves through the use of morphological characteristics, growth rate, carbon sources utilization and phylogenetic analysis. Methods and Results In all, 30Colletotrichumisolates recovered fromC. bonariensisleaves showing symptoms of disease were included in the present study. Based on the analysis of morphology and sequences, the isolates were distributed into sixColletotrichumspecies complexes. The concatenated alignment of GAPDH and ITS sequences showed that 20 out of 30 isolates were included in four species complexes which comprise the most important pathogens causing anthracnose in soybean or anthracnose and stalk rot in maize:C. truncatum,C. orchidearum,C. gloeosporioidesandC. graminicola. The remaining 10 isolates were included in theC. boninenseandC. destructivumspecies complexes or could not be assigned to any complex with the available information. Conclusion Weeds belonging to genusConyzaare host to soybean and maize potential pathogenic species ofColletotrichumand could have a role as inoculum reservoir for cross contamination in the agroecosystem. Significance and Impact of the Study The combined use of morphological, kinetics and physiological parameters of growth and phylogenetic analysis inColletotrichumisolates fromConyzaleaves allowed the detection of species complexes previously not identified in Argentina.