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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #301033
Title: Multistate evaluation of Brassica cover crop, biocontrol agent, and fungicide for integrated management of sheath blight

Author
item ZHOU, XING-GEN - Texas A&M Agrilife
item LIU, GUANGJIE - Texas A&M Agrilife
item ANDERS, MERLE - University Of Arkansas
item MAXWELL, HANDISENI - Texas A&M Agrilife
item ALLEN, TOM - Mississippi State University
item KLOEPPER, JOSEPH - Auburn University
item REDDY, MUNAGALA - Auburn University
item Jia, Yulin
item LU, SHIEN - Mississippi State University
item JO, YOUNG-KI - Texas A&M University
item WAY, MO - Texas A&M Agrilife

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/18/2014
Publication Date: 12/19/2014
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. 2014. Multistate evaluation of Brassica cover crop, biocontrol agent, and fungicide for integrated management of sheath blight. Proc. 35th Rice Tech. Work. Group Meet., New Orleans, LA, p.79. Feb 18-21, 2014. CDROM.

Interpretive Summary:

Technical Abstract: Sheath blight, caused by Rhizoctonia solani, is one of the most important diseases limiting rice production in the southern rice-producing states. The fungus survives between crops as sclerotia and mycelia in infected plant debris and serves as the primary inoculum. Infection starts when sclerotia and infected plant debris float to the surface of the flood water and come into contact with the rice sheaths. Currently, rice growers rely heavily on fungicides for control of this disease. However, excessive use of fungicides can cause a negative impact on the environment and lead to the development of fungicide resistance in the pathogen. The objective of this study was to develop an integrated management approach using brassica cover crop, a plant growth-promoting rhizobacteria (PGPR), and fungicide for sheath blight control. Brassica plants (Brassica spp.) contain glucosinolates. Once incorporated into soil, they are able to produce the gaseous isothiocynates that are toxic to R. solani and many other pathogens. Through this biofumigation process, brassica crops have the potential of suppressing sheath blight by reducing primary inoculum in soil. A field experiment was conducted in R. solani-infested plots in Texas, Arkansas, and Mississippi in 2012 and 2013 to evaluate the efficacy of brassica cover crop and PGPR alone and in combination with a reduced rate of Quadris (azoxystrobin) for the control of sheath blight. This trial was conducted as a split plot design with four replications. Main plots consisted of two cover crop treatments: 1) brassica ‘Caliente 199’ and 2) fallow. Subplots had five treatments: 1) Bacillus subtilis (PGPR strain MBI600), 2) combination of MBI600 and azoxystrobin at 4.5 fl oz/A, 3) azoxystrobin at 4.5 fl oz/A, 4) azoxystrobin at 9 fl oz/A, and 5) unsprayed control. The brassica crop was planted in fall or early spring and incorporated into soil before winterkill or in late spring. Seed of the rice cultivar Cocodrie or Presidio was treated with MBI600 prior to seeding. At the boot stage, plots were sprayed with MBI600 or azoxystrobin. Sheath blight severity was assessed near maturity. Plots were harvested using a plot combine and grain yield was determined. In Texas and Arkansas, sheath blight severity was lower in plots seeded with brassica cover crop than in plots left fallow in either year. However, the brassica cover crop treatment did not significantly increase grain yield compared to the fallow treatment. PGPR alone reduced disease severity but did not increase yield. Combined use of brassica cover crop or PGPR with azoxystrobin at the half rate or combination of all these three resulted in a consistent and significant improvement in disease reduction and yield increase, achieving similar efficacy as did azoxystrobin applied at the full rate. In Mississippi, PGPR applied alone or in combination with azoxystrobin at the half rate was effective in increasing yield on Cocodrie. Results of this study indicate that combined use of brassica cover crop and/or PGPR with a rate-reduced fungicide can offer new management options for sheath blight while reducing the use of fungicide in rice. This research was financially supported by the USDA/NIFA SRIPM Grant (2010-34103-21156).