Biological Potencial of Colletotrichum typhae H.C Greene mycoherbicide for Typha domingensis Pers

Abstract

The anthropic interference in aquatic ecosystems, favors the disordered colonization of T. domingensis, damaging the production of hydroelectric power and river traffic. Thus, the objective of this study was to evaluate the potential of C. typhae as a mycoherbicide in the control of T. domingensis, in vitro and in greenhouse. 107 samples of symptomatic T. domingensis leaves were collected in flooded areas of rivers in Brazil, with identification and isolation of the collected fungal species. The concentration of inoculum was determined to evaluate the incidence and severity of the disease, the influence of temperature on mycelial growth and conidia germination, the effect of temperature and leaf wetness period on T. domingensis infection by C. typhae and the host range test. The growth of the colonies of C. typhae was higher at 25 to 30 {o}C, there was no interference of the photoperiod on germination of the spores, but the highest percentage of germination occurred at 17.39 {o}C. The influence of environmental conditions on infection of inoculated leaves of T. dominguensis indicated that at 15 {degrees}C and the period of leaf wetness of 48 hours promoted the highest incidence of the disease, as well as the severity for the same period of leaf wetness. The specificity test showed that C. typhae is specific and pathogenic to T. domingensis. Being this the first report of the occurrence of this pathogen in aquatic macrophytes of this species and in T. domingensis in Brazil.