Browsing by Author "SAKSHI SUCHITA"
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ThesisItem Open Access EPIDEMIOLOGY AND MANAGEMENT OF BACTERIAL BLIGHT OF BEAN(UHF,NAUNI, 2021-09) SAKSHI SUCHITA; SAKSHI SUCHITA; KANSAL, SANDEEP; KANSAL, SANDEEPABSTRACT The present study on bacterial blight of bean revealed the disease in higher proportion in rainy season crop as compared to summer season crop being grown in Solan and Sirmaur districts of Himachal Pradesh. The pathogen isolated from the infected plants manifested smooth, shiny and dark yellow coloured colonies on Luria-Bertani agar medium and was identified as Xanthomonas axonopodis pv. phaseoli on the basis of various morphological and biochemical characters. The shape of bacterium was observed as straight rods with rounded edges having average size of 0.52×1.36μm. The pathogen exhibited initial symptoms much earlier in case of carborundum abrasion method as compared to pin prick method of inoculation on both potted plants as well as detached leaves. The symptoms initiated as the formation of small yellow fleck which later turned into brown irregular necrotic spots. The brown spots further coalesced together and resulted in blightning of leaves. The warm temperature (30°C) coupled with high relative humidity (>90%) and leaf wetness period (>16 h) were found conducive for bacterial blight development on bean. The pathogen survived in the infected seed for one year whereas, a significant decrease in viability was recorded with the increasing depth of burial of infected plant debris. Streptocycline was observed to be the most potent inhibitor of Xanthomonas axonopodis pv. phaseoli in in vitro evaluation studies while the in vivo studies revealed that seed treatment with Streptocycline 100ppm in combination with three periodic sprays of copper oxychloride 0.3% at seven days interval started after the initiation of disease was most promising in limiting the disease. Field evaluation studies also revealed seed treatment with Streptocycline @100ppm in combination with three periodic sprays of copper oxychloride @0.3% at 10 days interval started after disease initiation as most cost effective (1:16.38) in limiting bacterial blight of bean (67.60%) and enhancing the pod yield (100.79 q/ha).