| dc.description.abstract | Sheath blight caused by Rhizoctonia solani is one of the most important rice disease that can cause significant losses in grain yield and quality in the United States. Current management options for sheath blight consist of fungicides, tolerant cultivars and cultural practices. These options are not always very effective. Brassica plants have been used for soil fumigation to manage a variety of soilborne pathogens. Eleven plant species comprising of six Brassica juncea cultivars (Brand 199, Ruby Streak, Florida Broadleaf, Green wave, Red giant and Sheali Hong), two Brassica rapa cultivars (Southern Green and Napa), Brassica oleracea, Eruca sativa and Crotalaria juncea were evaluated for their efficacy on R. solani mycelia inhibition with or without soils collected from Texas, Arkansas or Mississippi rice fields. Evaluation of allyl isothiocynates (AITC) emission during the process of biofumigation was achieved by mixing B. juncea plant tissue at a rate of 0.25 or 0.5% (wt/wt) with either natural soil or pasteurized soil. The impacts of B. juncea soil amendment on the viability, aggressiveness, and sclerotia formation of R. solani AG1-1A was evaluated. B. juncea cover crop was integrated with host resistance and fungicide application to evaluate impact on rice sheath blight severity and rice yield.
Four B. juncea cultivars (Brand 199, Ruby Streak, Florida Broadleaf, Green wave) consistently provided the greatest inhibition in all the soil types tested. Mycelial inhibition increased with an increase of B. juncea application rate. Plant tissue mixed with natural soils resulted in significantly higher AITC emission than in pasteurized soils. B. juncea amendment reduced numbers of sclerotia formed from the mycelium exposed to soils amended with B. juncea. Viability and aggressiveness of sclerotia or mycelium was reduced in soils amended with 3.2 % (wt/wt) of B. juncea. B. juncea cover crop significantly lowered sheath blight severity in all three years and led to a significantly higher grain yield in 2013 as compared to the fallow control. B. juncea cover cropping can be added to the rice disease management practices to enhance the efficacy of the current integrated pest management program for sustainable control of sheath blight in rice.
Four B. juncea cultivars (Brand 199, Ruby Streak, Florida Broadleaf, Green wave) consistently provided the greatest inhibition in all the soil types tested. Mycelial inhibition increased with an increase of B. juncea application rate. Plant tissue mixed with natural soils resulted in significantly higher AITC emission than in pasteurized soils. B. juncea amendment reduced numbers of sclerotia formed from the mycelium exposed to soils amended with B. juncea. Viability and aggressiveness of sclerotia or mycelium was reduced in soils amended with 3.2 % (wt/wt) of B. juncea. B. juncea cover crop significantly lowered sheath blight severity in all three years and led to a significantly higher grain yield in 2013 as compared to the fallow control. B. juncea cover cropping can be added to the rice disease management practices to enhance the efficacy of the current integrated pest management program for sustainable control of sheath blight in rice. | en |
