Overview of Pestalotiopsis vismiae UTMC 5019 as a Potential Agent for the Biological Control of Hordeum spontaneum (Wild Barley)

Abstract

Hordeum spontaneum, which is one of the most important and troublesome annual weeds in crop fields around the world, causes extensive losses every year. The purpose of this study was to screen phytopathogenic fungi for biological control of this weed. For this purpose, firstly, 150 fungi were isolated from different soils in Iran. Thirty fungal strains were selected by consideration of their herbicidal activities against mature wild barley leaves. Common wheat was used as a negative control in all experiments. Finally, 6 strains showed necrosis lesions on wild barley leaves without any effects on wheat (control). The best result was achieved by Hcr99 isolate. Based on microscopic and Internal transcribed spacer-PCR (ITS-PCR) analysis, Hcr99 displayed 100% phylogenetically similarity to Pestalotiopsis vismiae (P. vismiae). 1×107 conidia/ml of P. vismiae showed the most suppression effect on weed seeds germination and rhizoid extension. Inoculum concentration of 1×106 and 1×107 conidia/ml provided significant results of weed controlling in greenhouse experiments. Host range study indicated that P. vismiae could induce disease symptoms in 4 weed plant species out of a total of 24 species belonging to 9 families.