Submitted to: Invasive Plant Science and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2014
Publication Date: 6/27/2014
Citation: Gibson, D.M., Vaughan, R.H., Biazzo, J., Milbrath, L.R. 2014. Exploring the feasibility of Sclerotium rolfsii VrNY as a potential bioherbicide for control of Swallowworts (Vincetoxicum spp.). Invasive Plant Science and Management. 7:320-327.
Interpretive Summary: Two emerging invasive plant species in the northeastern United States and southeastern Canada are pale swallow-wort and black swallow-wort. Earlier, we identified a naturally occurring fungus Sclerotium rolfsii VrNY, that was causing extensive mortality in pale swallow-wort populations within a county park. In this study, we evaluated the ability of this fungus to cause disease in close plant relatives, plant species typical of the natural resource area where the pathogen was initially found, and several important agricultural crops. Although these studies showed that most broadleaf vegetation may be susceptible to the pathogen, several plants including grasses were not affected, implying host range variability. Further laboratory testing of S. rolfsii and limited field testing at the initial discovery site will be needed in order to prevent premature rejection of this isolate as a potential management tool in natural resource areas overrun with these highly invasive weeds.
Technical Abstract: Pale swallowwort (PSW) and black swallowwort (BSW) are two viney milkweeds native to Europe that have increasingly become problematic and noxious weeds in eastern North America. An indigenous fungal isolate, Sclerotium rolfsii VrNY, was discovered causing significant mortality in a dense stand of PSW in a park in upstate NY. Although this fungus is a known pathogen with a broad host range, we evaluated the host potential of S. rolfsii VrNY on a limited range of related and non-related U.S. species as a critical first step to assess its suitability as a mycoherbicide for PSW and BSW. (-)-Antofine, a known antimicrobial and phytotoxic compound isolated predominantly from root tissue of PSW and BSW, had no effect on S. rolfsii VrNY. This isolate caused significant mortality on all broadleaf plants tested (Asclepias syriaca, As. curassavica, Apocynum cannabinum, Monarda fistulosa, Rudbeckia hirta, PSW, BSW) with the exception of Glycine max, and had no effect on the monocots Schizachyrium scoparium and Zea mays. Although these laboratory studies indicate that most broadleaf vegetation may be susceptible to the pathogen, S. rolfsii might have potential as a mycoherbicide in very limited natural environments where PSW and BSW have become the predominant vegetation. Further laboratory testing of S. rolfsii and limited field testing at the initial discovery site are needed in order to prevent premature rejection of this isolate as a potential management tool against these highly invasive weeds.