A comparative evaluation of bioagents and chemicals for the control of stalk rot of Sorghum caused by Dickeya dadantii

Abstract

Stalk rot sorghum caused by Dickeya dadantii (syn. Erwinia chrysanthemi) is a devastating sorghum disease and is highly detrimental to sorghum cultivation in tarai region of India. The bacterium disrupts and disintegrates vascular bundles of sorghum stem manifesting slimy soft rot symptom. In vitro studies on bioagents and chemicals revealed that among bioagents assessed Pseudomonas fluorescens strain Psf-173 and Trichoderma harzianum strain Th-14 surpassed the other biological control agents whereas among chemicals, oxytetracycline and tetracycline were outstanding than other chemicals and their combination products used for the control of stalk rot of Sorghum caused by D. dadantii. Field trial with pre-plant soil application had maximum reduction in disease severity in treatment with antibiotic oxytetracycline (28.18%) whereas trial with pre-plant soil application with one (34.49%) and two foliar spray (37.03%) showed maximum reduction in disease severity in treatment with P. fluorescens strain Psf-173. All the three field trials involving pre-plant soil application, pre-plant soil application and one foliar spray and trial with pre-plant soil application and two foliar spray revealed that biological control agent P. fluorescens strain Psf-173 alleviates symptom of stalk rot of sorghum and stimulates seed germination and plant growth.