Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2013
Publication Date: 4/3/2013
Citation: Handiseni, M., Brown, J., Zemetra, R., Mazzola, M. 2013. Effect of Brassicaceae seed meals with different glucosinolate profiles on Rhizoctonia root rot of wheat. Crop Protection. 48:1-5. Interpretive Summary: Organic soil amendments often have been promoted as a means to control soilborne plant diseases. However, the effective use of such an environmentally sensitive method of disease control has been impeded by a lack of understanding concerning the means by which amendments provide disease control. Tissues from plants belonging to the Brassicaceae have been promoted as a soil amendment for the control of soilborne plant diseases due to their production of glucosinolates, which yield anti-microbial compounds upon hydrolysis. In this study, brassicaceae seed meals, a waste residue resulting from oil seed extraction were evaluated for the ability to control soil inhabiting pathogens that limit the productivity of wheat production systems. Suppression of the fungal pathogen Rhizoctonia solani was obtained with intact seed meal or seed meal which had been modified in a manner the limited the release of biologically active chemistries after soil incorporation.
Technical Abstract: Tissues of plants in the family Brassicaceae contain glucosinolates, compounds whose hydrolysis results in the release of various bioactive products including isothiocyanates. The broad spectrum of biological activity of these glucosinolate hydrolysis products has led to the promotion of brassicaceae plant residues for use as an amendment for the control of soilborne plant diseases. Studies were conducted to determine the effect of Brassicaceae seed meals on suppression of winter wheat root infection by Rhizoctonia solani AG-8 infection of winter wheat. All intact brassicaceae seed meals significantly reduced infection by R. solani AG-8 and the quantity of pathogen DNA detected in wheat roots. Likewise, disease rating was reduced significantly in response to denatured seed meal amendments, but only denatured S. alba SM significantly reduced the quantity of R. solani AG-8 DNA detected in wheat root systems. These studies demonstrate that Brassicaceae seed meals can be used to manage disease incited by R. solani AG-8, however certain strategies, such as use of lower application rates and increased delay in seeding after SM amendment, may be necessary to minimize phytotoxicity.