Research Article of American Journal of Agricultural Research
Studies on interactions among bioagents colonized vermicompost, rhizospheric earthworms and stalk rot disease of sorghum caused by Erwinia chrysanthemi
Bhupendra Singh Kharayat and Yogendra Singh
Centre of Advance Faculty Training in Plant Pathology, College of Agriculture, G. B. Pant University of Agriculture and Technology, Pantnagar, PIN-263145, U.S Nagar, Uttarakhand (India)
Bioagents colonized vermicompost can be a crucial alternative natural biological control of stalk rot diseases of sorghum because of the hazardous effects of agrochemicals on non-targeted organisms and soil health. To study the interaction among bioagents colonized vermicompost with stalk rot disease of sorghum caused by Erwinia chrysanthemi, and earthworms of rhizospheric soil, pre-plant soil application of bioagents colonized vermicompost @ 2.5 kg/4 m2 and chemicals viz. Blitox-50, Bleaching powder, Streptocyclin and Tetracyclin @ 2.5% were done under field conditions. In analysis of earthworm’s population dynamics, maximum numbers of young earthworms per plant rhizosphere were observed with vermicompost colonized isolate Th-2 followed by vermicompost alone and vermicompost colonized isolate Psf-24. However, minimum number of young earthworms per plant rhizosphere was obtained with Bleaching powder. Maximum seed germination was recorded with vermicompost colonized isolate Th-2 followed by Th-R, Th-14, and Psf-12. Maximum number of earthworm’s heap of cast per plant rhizosphere was obtained in plants treated with vermicompost colonized isolate Th-2 followed by Psf-19, Psf-12 and Psf-18. Significant increase in biomass yield of sorghum plants were observed among all the treatments. However, maximum biomass yield was observed with vermicompost colonized isolate Th-2 followed by Psf-24. Maximum reduction of disease severity was recorded with vermicompost colonized isolate Th-2 followed by Th-14, Th-R and Psf-3. Present investigation suggests the effect of bioagents colonized on the dramatic increase in earthworm’s population (young and adult), earthworm’s body length, sorghum plant biomass yield and reduction in stalk rot disease severity. Our experiments have shown that bioagents colonized vermicompost have considerable potential not only improving plant growth, suppression of stalk rot disease severity significantly but also increasing soil earthworms when used as pre-plant soil amendment.
Keywords: Erwinia chrysanthemi, rhizospheric earthworms, sorghum, vermicompost, Trichoderma, Pseudomonas