Submitted to: Rice Field Day Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/20/2013
Publication Date: 7/1/2013
Publication URL: https://beaumont.tamu.edu/eLibrary/Newsletter/2011_Highlights_in_Research.pdf
Citation: Zhou, X., Liu, G., Anders, M.M., Maxwell, H., Allen, T., Kloepper, J.W., Reddy, M.S., Jia, Y., Lu, S., Jo, Y., Way, M. 2013. PGPR and its combined use with fungicide for control of rice sheath blight in the southern U.S. Rice Field Day Abstract. Beaumont, Texas Rice XIII (Special Section, Highlighting Research):17. Interpretive Summary:
Technical Abstract: Rice growers heavily rely on fungicides for control of sheath blight, caused by Rhizoctonia solani, the most important rice disease in Texas and other southern rice-producing states. Excessive use of fungicides can cause a negative impact on the environment and lead to the potential development of fungicide resistance. The objective of this study was to develop a new integrated strategy using plant growth-promoting rhizobacteria (PGPR) and fungicides for control of sheath blight while reducing the use of fungicides. A field experiment was conducted in R. solani-inoculated plots in Texas, Arkansas and Mississippi to evaluate the efficacy of PGPR strain MBI600 alone and in combination with a reduced rate of azoxystrobin for the control of sheath blight in 2010 (Texas only), 2011 (Texas only) and 2012. Strain MBI600, belonging to Bacillus subtilis, is the active ingredient in the biopesticide Integral®. The seeds of Cocodrie (highly susceptible to sheath blight) and Presidio (susceptible) were treated with strain MBI600 prior to seeding. At the boot stage, plots were sprayed with strain MBI600 at 109 CFU/ml alone or in combination with azoxystrobin (Quadris) at 0.08 (half rate) or 0.16 kg a.i./ha (full rate). Sheath blight severity was rated near harvest. Plots were harvested using a plot combine and grain yield determined. In Texas, strain MBI600 alone significantly reduced sheath blight severity in all 3 years and increased yield in 1 of 3 years. Combined use of strain MBI600 with azoxystrobin at the half rate further reduced disease and increased yield to the levels similar to azoxystrobin at the full rate in each year. In Arkansas, strain MBI600 alone did not affect disease severity and yield but its combination with azoxystrobin at the half rate significantly reduced disease and increased yield. Its efficacy was comparable to that of azoxystrobin at the full rate. In Mississippi, strain MBI600 applied alone or in combination with azoxystrobin at the half rate was effective in increasing yield on Cocodrie. The results of this study indicate that combined use of PGPR with a fungicide can be an effective integrated approach to managing sheath blight and reducing the usage of fungicides on rice.