Location: Foreign Disease-Weed Science Research
Title: A fungal pathogen (Colletotrichum shisoi) reduces biomass, flowering, and competitive ability of invasive beefsteak plant (Perilla frutescens)Author
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Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 1/10/2023 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Beefsteak plant (Perilla frutescens) is an invasive weed in North America, where it excludes native vegetation in natural areas and can cause respiratory illness in grazing livestock. An adventitiously introduced fungal plant pathogen (Colletotrichum shisoi) is being evaluated for biological control activity. The effects of pathogen infection on perilla biomass, flower production, and competition with native plants were recorded under controlled conditions. A dose-response experiment determined a concentration of 1x107 fungal spores/mL aqueous suspension applied to perilla seedlings reduced biomass by 88% relative to plants treated with a sterile water control. Application of the same spore concentration to adult perilla plants at the onset of floral development reduced aboveground plant biomass by 34% and the number of flowers produced at plant maturity by 45%. A modified partial additive competition experiment was performed using perilla, bee balm (Monarda didyma), and mountain-mint (Pycnanthemum virginianum) grown with and without application of the pathogen. The native plants produced 80% less biomass in the presence of healthy perilla compared to growth alone, and application of the pathogen restored native plant biomass to levels observed in the absence of perilla. These results suggest severe pathogen infections might decrease the invasiveness of perilla by reducing fecundity and competitive ability. |
