Author(s):

Ashok Kumar Koshariya, Indra Kumar, Anil S Kotasthane, Toshy Agrawal and Priyanka

Abstract: Rice sheath blight, caused by the fungal pathogen Rhizoctonia solani Kuhn [Sexual stage: Thanetophorus cucumeris (Frank) Donk] is one of the major production constraints in rice-growing countries of the world. Under conditions favoring disease, up to 50% of grain yield may be lost (Marchetti and Bollich 1991). Control may be achieved with fungicides (Groth 2008), but cost and the potential for development of pathogen resistance make plant genetic resistance preferable. Plants can be induced locally and systemically to become more resistant to diseases through various biotic or abiotic stresses. The best characterized signal pathway for systemically induced resistance is SAR (systemic acquired resistance) that is activated by localized infections with necrotizing pathogens. It is characterized by protection against a broad range of pathogens, by a set of induced proteins and by its dependence on salicylic acid (SA) Various chemicals have been discovered that seem to act at various points in these defense activating networks and mimic all or parts of the biological activation of resistance. Resistance inducing chemicals that are able to induce broad disease resistance offer an additional option for the farmer to complement genetic disease resistance and the use of fungicides. If integrated properly in plant health management programs, they can prolong the useful life of both the resistance genes and the fungicides presently used Thifluzamide is a member of the carboxamide class of fungicides which is single-site inhibitors of the succinate ubiquinone reductase or succinate dehydrigenase (Sdh) complex in the respiratory chain (FRAC 2007) interfere with fungal respiration via their inhibitory effect on succinate dehydrogenase within the tricarboxylic acid cycle. (O’Reilly1995). We have observed Thifluzamide to be effective in controlling rice sheath blight and therefore the fungicide can fit into resistance management system by integrating in spray schedules in potential rice growing tracts.

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