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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #394249
Research Project: Discovery and Development of Microbial-Based Biological Control Agents for Use Against Invasive Weeds in the United States

Location: Foreign Disease-Weed Science Research

Title: Fungal plant pathogen Colletotrichum shisoi identified as a potential biological control agent of invasive Perilla frutescens in the United States

Author
item Fulcher, Michael
item STALEY, CHRISTIAN - Hood College

Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2024
Publication Date: 4/18/2024
Citation: Fulcher, M.R., Staley, C.T. 2024. Fungal plant pathogen Colletotrichum shisoi identified as a potential biological control agent of invasive Perilla frutescens in the United States. BioControl Science and Technology. 34(4):375-388. https://doi.org/10.1080/09583157.2024.2343110.
DOI: https://doi.org/10.1080/09583157.2024.2343110

Interpretive Summary: Perilla mint is a foreign invasive weed that causes respiratory illness in livestock and outcompetes native plants. Developing a biological control agent for perilla mint would provide an environmentally sound and economical alternative to managing this weed with chemical herbicides and physical removal. The fungus Colletotrichum shisoi was found in Frederick County, Maryland with the help of the National Park Service. This plant pathogen reduced the growth of perilla mint and did not damage desirable mint species, including wild native plants and commercially cultivated herbs. The fungus will be used by scientists researching improved management practices for perilla mint.

Technical Abstract: Perilla frutescens (L.) Britton, an annual plant in the mint family, is considered invasive in the United States where it excludes native vegetation in natural areas and can cause respiratory illness in livestock. An effective biological control agent would improve perilla management, but none have been developed or proposed. This study investigated the biocontrol potential of a fungal pathogen, Colletotrichum shisoi, recently found infecting perilla in North America. The growth rates and morphology of seven Colletotrichum shisoi isolates were recorded. A virulence assay was performed on two perilla accessions, and the number and size of foliar lesions produced were used to select a single isolate for further evaluation of biocontrol efficacy and specificity. Perilla seedlings treated with a low dose of Colletotrichum shisoi 21-072 developed shorter shoots and roots than mock inoculated plants, and seedlings treated with a high dose of the pathogen had a 100% mortality rate. Additional perilla accessions were susceptible to C. shisoi, but no other plant species developed disease during host range experiments. These results suggest C. shisoi 21-072 could be an effective antagonist of perilla and likely poses a low risk of non-target impacts.