Link to home

Investigation of leaf blotch and blight disease pathogens of Microstegium vimineum and screening for its potential biological control agents

Sheng Qiang: Weed Research Laboratory/Nanjing Agricultural University

<div><em>Microstegium vimineum</em> (Trin.) A., native to East and Southeast Asia, is an annual gramineous weed that has invaded the eastern United States of America and rapidly become a vicious invasive weed in the country. We evaluated a large number of microorganisms associated with leaf-blotch and leaf-blight diseases (434 leaf samples) on the weed in 11 Chinese provinces from 2014 to 2016 for potential biocontrol agents. The assessment was based on Koch’s postulate, morphological and molecular identification of the organisms. A total of 381 isolates, including 82 pathogenic fungal isolates, were obtained. These fungal pathogens belonged to 19 species of 10 common genera, including <em>Alternaria</em>, <em>Bipolaris</em>, <em>Corynespora</em>, <em>Curvularia</em>, <em>Drechslera</em><em> Exserohilum</em>, <em>Gloeocercospora</em><em> Nigrospora</em>, <em>Pestalotiopsis</em> and <em>Phoma</em>. Among them, five species that caused apparent disease on <em>M. vimineum</em> had not been reported on the host previously. Furthermore, eight isolates with strong virulence to this weed were assessed for biocontrol efficacy and host specificity in both controlled- environment and field trials; the candidates <em>B. panici-miliacei,</em> <em>B. maydis</em> and <em>Curvularia geniculata </em>demonstrated the greatest potential as biological control agents against <em>M. vimineum</em> and other grassy weeds.</div>