In vitro evaluation of biocontrol agents against Sclerotium rolfsii Sacc. causing rootrot of sugarbeet

Abstract

Eighteen rhizosphere soil samples of healthy sugarbeet plants were collected from sugarbeet growing regionsof India for isolation of biocontrol agents. Six Trichoderma harzianum, one T. viride and sixteen Bacillus subtilis isolateswere isolated. Efficacy of fungal and bacterial bioagents against Sclerotium rolfsii was evaluated by following dual culturetechnique. Among the Trichoderma isolates evaluated, significantly highest inhibition was recorded in T. harzianum.Institute of Organic Forming(IOF), University of Agricultural Sciences, Dharwad (UASD) the isolate (69.41 %) followedby T. viride Kalparuksha (65.88%). Least inhibition was recorded in T. viride isolate TvA5 (57.65 %) followed byT. harzianum isolate ThA2 (58.04 %). Among the B. subtilis isolates tested, significantly highest inhibition was noticedin B. subtilis isolate BsA6 (48.92 %) followed by isolate BsB6 (46. 77 %). Least inhibition was recorded in B. subtilisisolate BsA8 (8.06 %) followed by isolate BsA3 (9.14 %)