Laboratory, greenhouse and field based assessment of sodium acetate for control of plant bacterial speck disease

Laboratory, greenhouse and field based assessment of sodium acetate for control of plant bacterial speck disease

Summary

The objective of phase one will be finished soon. We confirmed that spray of low concentrations of sodium acetate significantly compromised bacterial growth and disease symptom development of Pseudomonas syringae pv. tomato, the causal agent of bacterial speck disease on tomato, suggesting the potential of Natrium acetate (NaAc) as a new method to control Pseudomonas pathogens. The best concentration of NaAc recipe has been identified as 1mM. Undergoing experiments include determining the best timing for spraying NaAc solution. We plan to finish the first phase by April 2009, and to start the second phase by testing the optimized NaAc recipe in the field assay.

Objectives/Performance Targets

There are two phases of this research.

The first phase will be the assessment and optimization of NaAc recipes against bacterial speck on tomato and bean by testing different concentrations of spray (from 0.1mM to 100mM), examining the timing of spray (days and times before or after bacterial inoculation), and testing NaAc application against other bacterial pathogens (such as Xanthomonas on tomato and cabbage). This phase will be finished in laboratory and greenhouse facilities on the Kansas State University campus in Manhattan, KS. Inputs for the first phase will be graduate student labor, laboratory and greenhouse expense for proposed experiments.

The second phase of this project will start in spring of 2009. We will take the optimal NaAc recipes obtained from the first preliminary phase to the larger-scale field trials at the Rocky Ford Research Center Farm in Manhattan and the K-State Horticulture Research and Extension Center in Olathe, KS. Two cropping cycles will be done through the summer and fall of 2009 to ensure good statistical analysis. Inputs for the second phase will include intensive graduate student labor, and collaboration with farmers and plant pathologists. Farmer cooperators will have the chance to join further study as an integral part of sustainable agriculture project.

Accomplishments/Milestones

1. Of concentrations from 0.1mM to 100mM, the best concentration of NaAc for reducing bacterial growth of Pseudomonas syringae pv. tomato DC3000 on tomato has been determined as 1mM.

2. Spraying NaAc solution (1mM) on leave surface gave better result than injecting by syringe, which didn’t show clear suppression of bacterial growth (Pseudomonas syringae pv. tomato DC3000) in tomato plants.

3. Spraying NaAc solution (1mM) reduced bacterial growth (Pseudomonas syringae pv. tomato DC3000) up to 20 folds compared to water control after 5 days of inoculation.

4. Spraying NaAc solution 1 or 2 days before/after bacterial inoculation also helped to reduce bacterial growth a little bit, but not as good as spraying NaAc solution at the same time as bacterial inoculation.

5. NaAc assay failed to compromise bacterial growth of Pseudomonas syringae pv. phaseolicola on bean plants and Xanthomonas campestrispv pv. campestris on cabbage plants.

Impacts and Contributions/Outcomes

We confirmed that spray of low concentrations of sodium acetate significantly compromised bacterial growth and disease symptom development of Pseudomonas syringae pv. tomato, the causal agent of bacterial speck disease on tomato, suggesting the potential of NaAc as a new method to control Pseudomonas pathogens. By taking our preliminary data to a larger scale, we will be able to address concerns of farmers in the application of proposed NaAc method. With the results from controlled field trials, we will have greater opportunity to gain more useful information of mature NaAc recipes.

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