Antifungal activity of PGPR and sensitivity to Agrochemicals

Antifungal activity of plant growth promoting rhizobacteria (PGPR) was studies by inoculation of fungal pathogen in bacterial mass in plate by inhibition method. PGPR isolates significantly inhibited the mycelial growth of Seclrotium rolfsii, Fusarium oxysporum, Rhizoctonia bataticola and Colletotrichum dematium. Maximum inhibition was recorded by isolate CORb-9 (62.6%) in Sclerotium rolfsii, CoRb-8 (56.9%) in Fusarium oxysporum, CoRb-10(55.1%) in Rhizoctonia bataticola, CoRb-9 (61.2%) in Colletotrichum dematium at fifth days of inoculation, while interaction among PGPR and Trichoderma viride was not recorded anti detrimental effect on the growth of each other. Sensitivity of PGPR isolates to different pesticides viz. carbaryl, carbendazim, copper oxychloride, thiram, vitavax and paushamycin was tested tubidometricalily at 620nm. PGPR was found to be sensitive to carbaryl 50WP @ 0.3% (CoRb- 1, 12.0%), vitavax @ 0.25% (CoRb-8, 20.4%), thiram @ 0.3% (CoRb-3, 44.6%), carbendazim (CoRb -1, 0.1%), copper oxychloride @ 0.3% (CoRb-6, 27.5%). Antibiotic paushamycin @ 250 ppm showed maximum inhibition of growth of PGPR isolates. Maximum suppression in growth was observed in CoRb -2 (48.2%) at 72 hrs in COC at 0.3%.