Reaction of major weeds and some rice cultivars to Alternaria pellucida- a potential biocontrol agent

Sagitaria trifolia, Alisma plantago-aquatica and Echinochloa spp. are among the most important damaging weeds in paddy fields. In this research, Alternaria pellucida was isolated from the weeds and then its pathogenicity effects was examined on these weeds and five other rice cultivars, including two bred (Sepidroud and Khazar) and three landraces (Ali Kazemi, Hashemi and Binam), in a completely random design with three replications in greenhouse conditions. A. pellucida caused a high disease rating on the weeds compared to rice cultivars. Results revealed that A. pellucida caused high disease ratings in S. trifolia, E. crus-galli, A. plantagoaquatica, and E. oryzicola, respectively. The reaction of weeds to this fungus, in terms of disease rating, was significant while rice cultivars showed no significant reaction. In addition, the fungus caused a significant reduction of height, fresh weight and dry weight of the evaluated weeds, whereas no significant reduction was observed in the dry weight of rice cultivars. Nevertheless, the fresh weight and height of cultivars showed significant reactions. Based on the results of this research, A. pellucida could be introduced as a potential mycoherbicide for controlling these weeds.