Submitted to: World Journal of Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2008
Publication Date: 6/5/2008
Publication URL: http://handle.nal.usda.gov/10113/60770
Citation: Boyette, C. D., Weaver, M. A., Hoagland, R. E., and Stetina, K. C. 2008. Submerged Culture of a Mycelial Formulation of a Bioherbicidal Strain of Myrothecium verrucaria with Mitigated Mycotoxin Production. World Journal of Microbiology and Biotechnology. 24(11):2721-2726. Interpretive Summary: The fungus Myrothecium verrucaria (MV), originally isolated in Mississippi, is effective in controlling several weeds, including kudzu. Limiting factors for scaled-up experiments include: difficulty in producing fungal spores on solid-substrate media, and more importantly, the presence of mycotoxins (macrocyclic trichothecenes) in solid-substrate, (spore-based) inoculum. We have discovered that MV mycelium can be rapidly produced (48 h) using inexpensive agricultural products, e.g., soyflour-cornmeal medium, and this formulation is highly effective in controlling kudzu in naturally-infested test plots. Of equal or perhaps more significance, HPLC analyses revealed that macrocyclic trichothecene production in MV mycelium is greatly reduced or eliminated, thereby providing a safe, highly efficacious bioherbicidal product. These findings may improve probability of EPA registration and commercial development of this bioherbicide.
Technical Abstract: A mycelial formulation of the fungus Myrothecium verrucaria (IMI 361390) was shown to be highly efficacious in controlling the exotic invasive weed kudzu. The mycelium can be rapidly (48 h) produced in several media including soy flour-cornmeal medium. HPLC analyses revealed that the mycelial formulation was either void of, or produced undetectable amounts of the trichothecene mycotoxins roridin a and verrucarin a, resulting in a safe, effective bioherbicidal product. We anticipate that these findings should improve the probability of EPA registration and subsequent commercial development.