2006 Annual Report 1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? Management of invasive weeds is a necessary but expensive challenge. Weed control with synthetic chemicals currently exceeds $4 billion annually, excluding immense indirect costs to the producer, consumer and the environment, and has also resulted in development of resistant weed biotypes. Over the past decade, many chemical herbicides have been lost due to lack of re-registration, competition from other products, and the development of genetically modified crops with resistance to broad-spectrum herbicides such as glyphosate. The majority of herbicide usage is for agronomic areas or turf, but there are few herbicides registered for (or being developed for) smaller markets or niche weed problem areas such as control of kudzu, and invasive weeds in non-cropland areas. Furthermore, chemical weed control is not an option in organic cropping systems and in sensitive natural habitats. Herbicides have not been successful in managing many invasive plant species, such as kudzu, an important host of Asian soybean rust. Classical pathogen mediated biocontrol of weeds has also had only limited success; due in part to a dependence on optimal weed pathogen environment interactions and the small market potential associated with highly specific (one weed species) biocontrol agents released with this approach. An augmentative deployment strategy for a bioherbicide can achieve effective control through multiple applications. Broad-spectrum bioherbicides improve a product's marketability, and by embracing an augmentative deployment strategy the agent can achieve effective control through repeated applications. The fungus Myrothecium verrucaria (MV) is a bioherbicide with high potential. It is one of the most effective biocontrol agents against kudzu, and controls many other invasive plant species, but it also produces mycotoxins. A major goal of this project is to make safe formulations of MV with enhanced efficacy and reduced toxicity to enable product development. The assessment of the risks associated with deployment of biocontrol agent requires knowledge of its epidemiology, post-release survival, spread, and interaction with the natural ecological microbial community. Sensitive detection of a pathogen at sites distant from deployment or long after application requires molecular tools, which have only recently been developed. Information generated from this research will expand current knowledge of weed:pathogen interactions, while addressing needs of federal and regional research priorities, regulatory agencies (e.g. EPA, APHIS), the agrochemical industry, consultants, environmental scientists, farmers, land managers, and the general public. Relevance to ARS National Program Action Plan: National Program 304 Crop Protection and Quarantine: This program falls within Component B (Weed Science), Sub-component IX (Biological Control of Weeds). This project will focus on: 2.A (Agent discovery, selection and risk assessment); 2.B (Efficacy and mass production of augmentative agents); 2.C (Field evaluation); and 2.D (Combining biocontrol agents). This plan may also contribute to Component I: Preplant Soil Fumigation Alternatives of NP 308 "Methyl Bromide Alternatives." 2.List by year the currently approved milestones (indicators of research progress) Year 1. (FY 2006) 1. Initiate/develop/optimize trichothecene-deficient MV formulations. 2. Conduct MV/glyphosate (and other herbicide) compatibility assessments. 3. Develop MV trichothecene inhibition assays. 4. Initiate/develop MV mutants with reduced trichothecene levels. Year 2. (FY 2007) 1. Complete MV trichothecene-deficient fermentation studies. 2. Develop micro-encapsulation methodologies for MV. (Milestone modification request was approved by NPL to direct encapsulation research on MV; also approved request to move milestone from FY 2006 to FY 2007). 3. Establish research to characterize MV genotypic/phenotypic diversity. 4. Identify biomarkers for following fate of MV in the environment. (Milestone modification request was approved by NPL to direct biomarker research on MV; also approved request to move milestone from FY 2006 to FY 2007). 5. Trichothecene-deficient mutants identified. 6. Initiate and complete cloning of MV Tri-genes. Year 3. (FY 2008) 1. Improved MV formulation assessment completed. 2. MV on-site field assessment on kudzu completed. 3. Trichothecene biosynthesis inhibitors identified. 4. MV mycotoxin and pathogenicity diversity characterized. 5. Milestone modification requested and approved by NPL to direct research towards MV encapsulation; also approved to move from 2008 to 2009 in order to obtain two sets of field data. Year 4. (2009) 1. Field assessments of MV formulations and encapsulation completed. 2. MV fermentation/inhibitor systems developed. 3. MV:weed defense interactions characterized. 4. Complete post-release MV monitoring and risk assessment. 5. Tri-gene expression documented. 4a.List the single most significant research accomplishment during FY 2006. The new project was only approved in February 2006. Laboratory, greenhouse, and field experiments have been initiated in each of the projected milestones. 4b.List other significant research accomplishment(s), if any. None 4c.List significant activities that support special target populations. None 4d.Progress report. None 5.Describe the major accomplishments to date and their predicted or actual impact. We have discovered and patented several plant pathogens and biologically-based compounds which are highly effective in controlling several agronomic, horticultural, and exotic invasive weed species. For example, we have shown that the fungus Myrothecium verrucaria can effectively control kudzu and other invasive weeds in field trials. We have developed and patented formulations, such as invert, oil emulsions, and granular, which greatly enhance the biocontrol efficacy of bioherbicides. For example, we have demonstrated that the fungus Colletotrichum truncatum is highly effective in controlling the weed hemp sesbania in soybean, cotton, and rice fields when formulated with corn oil or invert emulsions, or with pre-emergence applications of fungus-infested wheat-gluten granules (Pesta) or rice grain formulations. Various surfactants, such as Silwet L-77 enhanced the virulence of C. truncatum for hemp sesbania control, and C. gloeosporioides for sicklepod control. We have discovered important biochemical defense mechanisms that are triggered in several weeds when the plants are challenged by pathogens such as Myrothecium verrucaria, Alternaria cassiae, A. crassa and C. truncatum, and herbicides such as glyphosate. Understanding such mechanisms is paramount to finding compounds that can inhibit weed defenses and promote pathogenesis and thereby increase pathogen efficacy. We have discovered that low levels of glyphosate can synergize diseases of several different pathogen:weed host systems. The impact of some of these discoveries could result in improved bioherbicide efficacy and ultimately to commercial products, and to a reduction in the overall usage of chemical herbicides. 6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Assisted in organization of USDA-ARS sponsored Kudzu Biocontrol Workshop, Stoneville, MS. Attended by NPL and several divergent researchers and stakeholders, e.g., forestry, DOT, and homeowners. Two members of the research unit made oral presentations concerning biocontrol of kudzu and risk assessment. Compiled proceedings and submitted final report to NPL May, 2006. Met with representatives from Novozymes Biologicals, Inc. to discuss bioherbicide commercialization; oral overview presentation of SWSRU bioherbicide research. Met with representative of Prophyta Ltd. to discuss commercial development of Myrothecium verrucarria. Presented posters at the Weed Science Society of America, New York, New York. Presented posters at the Mississippi Weed Science Society, Stoneville, MS. Mentored student presented poster at the Mississippi Academy of Science, Jackson, MS (Won second place). Attended and presented invited poster at 2006 Agronomic Crops Field Day, Delta Research and Extension Station, Stoneville, MS. 7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Boyette, C.D., Hoagland, R.E., and Weaver, M.A. 2006. Interaction of the fungus Colletotrichum truncatum and glyphosate for controlling hemp sesbania in glyphosate-resistant soybean. Phytopathology. 96:S15. Weaver M.A., Hoagland, R.E., and Boyette, C.D. 2006. Compatibility of the bioherbicide Myrothecium verrucaria with selected pesticides. Phytopathology. 96:S121.