Biointensive Management of Sheath Blight of Rice in Tarai and Bhabar Regions of Uttarakhand

Abstract

Sheath blight of rice caused by Rhizoctonia solani is one of the most important diseases newlineworldwide; causing considerable yield losses. The estimation of losses due to sheath blight of newlinerice in India has been reported to be up to 54.30%. As a consequence of the above mentioned newlinefacts, ecofriendly approaches were explored in this investigation. To achieve these goal present newlinestudies on Biointensive management of sheath blight of rice in Tarai and Bhabar region of newlineUttarakhand had been conducted. The result of the study reveals that major varieties of rice newlinegrown by the farmers of Tarai and Bhabar region were Mansuri, Tilak Chandan, Inderasan, newlineHR47, PR113, PR21, PR13, Pusa Basmati, U.S.312 and other hybrids. Sheath blight, bacterial newlineleaf blight, false smut, rice blast and brown spot were the major diseases in the area. In district newlineNainital, the disease incidence ranged between 11.33% and 34.00% whereas, disease severity newlineranged between 24.00 % and 57.33%. In the district Udam Singh Nagar the maximum disease newlineincidence (39.33%) was observed and minimum disease incidence 27.00% was recorded. The newlinemaximum disease severity 64.66 % was observed while, the minimum disease severity was newline25.00%. The pathogen Rhizoctonia solani was isolated from the infected sheath of rice plant, newlinecollected from farmer s field which was further identified and characterized on the basis of newlinemorphology and through molecular Sequencing. The Sequences of ITS were submitted to NCBI newlineGenBank and the accession number allotted is SUB11543577. In dual culture best two potential newlineisolates of biocontrol agents were selected Pseudomonas fluorescens (27)(PF) and Trichoderma newlineharzanium (47)(Th). Their different combinations with Herbal Kunapajala (HKJ) were tested in newlineglasshouse, experimental field and farmers fields against sheath blight pathogen Rhizoctonia solani. The newlinemaximum plant vigour index was found in treatment combination Pseudomonas fluorescens (27) + newlineTrichoderma harzanium (47) +Herbal Kunapajala, seed treatment(ST), soil drenching and three foliar newlineapplications (FS). Minimum disease severity and disease incidence at 30 DAS and 60DAS, maximum newlinePAL, PPO and PO activity, was also recorded in the same treatment. In field experiment the maximum newlinepopulation of biocontrol agents after 60 days of transplanting cfu/g soil for Trichoderma spp. newline(32.33×104) and Pseudomonas spp. (36.33×104) in rhizosphere and in rhizoplane. Maximum newlinecfu/g soil for Trichoderma spp. (24.67×104) and Pseudomonas (24.0×104) was observed in newlinetreatment Th + PF + HKJ [ST+Drenching+FS]. At experimental and farmers field minimum newlinedisease severity, disease incidence at 60DAT was recorded in treatment Th + PF + HKJ newline[ST+Drenching+FS] and was at par with the chemical treatment Carbendazim but, the maximum newlineyield was obtained in the treatment Th + PF + HKJ [ST+Drenching+FS] due to the maximum newlinegrowth promotion activity shown in the treatment. Therefore the recommendation of present newlineinvestigation can be exploited under biointensive disease management programme for newlinesustainable cultivation of rice in Tarai and Bhabar region of Uttarakhand. newline