Jarial, KumudHallan, Somya2022-12-072022-12-072021-10-10https://krishikosh.egranth.ac.in/handle/1/5810190432In survival studies, it was found that Xanthomonas cucurbitae could survive in soil containing plant debris for up to 12 months and 15 cm depth. The bacterial concentration obtained after 6 and 9 months of duration was found to more than the bacterial concentration obtained after 12 months in pumpkin as well as bottle gourd (1.18 x 105 and 1.20 x 105cfu/ml respectively). Concentration of the bacteria was found to be decreased with increase in soil depth as minimum bacterial concentration (1.18 x 105cfu/ml) was recorded at 15 cm depth in both the isolates. The study showed 100 per cent incidence of pathogen in all the seeds of the varieties / hybrids of each crop. Among various chemicals evaluated in vitro against the bacterium, in case of pumpkin isolate, Bordeaux mixture, with 20.99 mm diametric zone of inhibition, proved most effective in controlling the bacterium. In case of bottle gourd isolate, copper oxychloride with 24.92 mm zone of inhibition proved most effective. Out of various hot water treatments evaluated, temperature treatments of 45 and 48℃ completely failed to manage the pathogen. Minimum number of infected seedlings were recorded at 55℃ for both the isolates but at this temperature, the seed germination was significantly reduced. Among the various chemicals tested as seed dip treatments, streptocycline and copper oxychloride were found to be the most effective. Maximum seed germination for both isolates, was observed after 180 minute dip duration. Minimum number of infected seedlings were recorded, in case of pumpkin, in streptocycline (37.64%) followed by copper oxychloride (39.55%). And in case of bottle gourd, minimum number of infected seedlings were recorded in copper oxychloride (40.80%) followed by streptocycline (42.62%). In both the isolates, minimum number of infected seedlings were recorded in 720 minutes (40.55 and 43.48 %, respectively) followed by that in 180 minute duration (44.40 and 47.98 %, respectively). For both pumpkin and bottle gourd, minimum number of infected seedlings were recorded in a combination dip treatment of streptocycline (100 ppm) plus copper oxychloride (3000 ppm) for 3 hour duration (16.33 and 15.67 %, respectively). Chemical seed dip treatment with streptocycline (100 ppm) and copper oxychloride (3000 ppm) for 3h was found effective in controlling the bacterium under pot conditions as minimum disease severity was recorded in this treatment for both pumpkin and bottle gourd (18.00 and 22.00 %, respectively).EnglishThesis