Location: National Programs
Project Number: 0500-00053-003-05-G
Project Type: Grant
Start Date: May 3, 2009
End Date: May 2, 2014
Project Title 1 - Enhancement of Biocontrol of FHB/DON Through an Understanding of Microbial Ecology: The emphasis of this proposal is on microbial ecology, particularly the temporal, spatial, and physical interactions between B. subtilis and Fusarium graminearum on wheat floral structures. Objectives of this research are to: 1) Continue to evaluate the temporal population dynamics of Bacillus subtilis and Fusarium graminearum on wheat spikes under varying environmental conditions; and 2) Determine the contribution of antifungal lipopeptides to biological control by Bacillus subtilis. Project Title 2 - Within-Field Inoculum from Corn Debris and the Management of FHB/DON: Our experimental objective is to quantify the relative contribution of within-field corn debris as an inoculum source of Gibberella zeae for Fusarium head blight and DON contamination in 20 variable wheat or barley environments over two years, all in regions where corn is the predominant crop in the agricultural landscape and corn debris is left on the land surface over large areas. Our research addresses Goal #3, to develop a full understanding of specific factors influencing infection and toxin accumulation that can be used to develop the next generation of scab and DON risk assessment measures. Specifically we will (1) elucidate the contribution of local inoculum sources to the temporal and spatial development of FHB epidemics, and this knowledge will, in turn, (2) help refine models for FHB risk assessment. Results from this study will increase our understanding of the spread of G. zeae from a local source of inoculum and will be of immediate value in determining the relative risk of infection of wheat by G. zeae from within-field sources of inoculum. Project Title 3 - Integrated Management Strategies for FHB and DON in New York: As part of a multi-state Coordinated Project, field experiments will be conducted to investigate the effects of variety resistance and fungicide/biocontrol application on FHB and DON accumulation in winter wheat under natural conditions. Overarching project objectives are to 1) Evaluate the integrated effects of fungicide and genetic resistance on FHB and DON in all major grain classes in different cropping systems; 2) Conduct a quantitative synthesis of the integrated effects of fungicide and resistance on FHB/DON and the influence of region-specific factors on the overall efficacy of this integrated approach; and 3) Develop “best-management practices” for FHB and DON.
Project Title 1: We will utilize both traditional dilution plating onto agar media as well as real time PCR methods to monitor the population dynamics of B. subtilis and F.graminearum on wheat heads. DON in grain will be quantified by GC/MS at VirginiaTech and correlated with observed population dynamics. We will utilize LC and MS methodologies and growth inhibition assays to identify threshold inhibitory levels of the lipopeptides produced by B. subtilis. From this research we will determine if biocontrol in this system is positively associated with threshold populations of bacteria, and we will discover how environmental conditions alter these critical levels. Finally, we will determine which and at what threshold level of the major groups of lipopeptides produced by B. subtilis are necessary for biocontrol efficacy. Project Title 2: Building on techniques perfected in New York and Virginia in 2007-2008, we will use a marked (AFLP) isolate, release-recapture experimental approach to assess relative contribution of localized clonal inocula to infection of cereal heads at the source and at more than 100 feet from the source in commercial wheat and barley fields otherwise lacking corn or cereal debris. We expect that concentrated clonal inoculum may overestimate the contribution of local inoculum to FHB and DON, so we are also employing replicated microplots in each experimental field with naturally overwintered corn debris collected from sources close to those same wheat and barley fields. The research will be conducted in two commercial-scale wheat or barley fields per season in Illinois, Missouri, Nebraska, New York, and Virginia. All field sites are in regions with considerable acreage of over-wintered corn residues nearby. Project Title 3: Two independent experiments will be conducted at the Cornell University Musgrave Research Farm in New York in 2009 so that integrated management is examined under two different cropping environments that are common in New York. One experimental environment will involve planting wheat in late September into soybean stubble. The second experimental environment will involve no-till planting of wheat into corn stubble following grain corn harvest in late October. This will provide two contrasting environments in terms of exposure to within-field inoculum (expected to be greater in corn debris) as well as to different weather conditions at the time of flowering and early grain development. The experimental design for each experiment will be a split plot, with four varieties as the whole-plots and four spray treatments as the sub-plots. There will be four replicate blocks. In each main plot within each block, there will be four randomized sub-plots of spray treatments: 1) Prosaro (6.5 fl oz/A + 0.125% Induce); 2) Bacillus subtilis TrigoCor 1448 + 0.125% Induce; 3) Bacillus subtilis TrigoCor 1448 + 0.125% Induce + Prosaro (6.5 fl oz/A); and 4) not treated. Fungicide and biocontrol application will be made at the time of early anthesis (Feekes GS 10.5.1) for each variety. Each of the four varieties chosen for two years of study is being grown commercially in New York.