Senapati, Akshaya KumarTripathy, Abhisek2024-08-072024-08-072023-11-22https://krishikosh.egranth.ac.in/handle/1/5810212988Recently due to a decline in chilli (Capsicum annuum L.) production, India stands third in all over worlds’ production statistics. The decline in chilli production has been attributed to the diseases linked with plants like bacterial wilt causing the major share of crop loss. Year by year chilli production in Odisha is reducing for several plant diseases attack from which bacterial wilt holds a higher position. Bacterial wilt of chilli caused by Ralstonia solanacearum is a very disparaging disease in the coastal vegetable belt of Odisha. The disease is complicated and many cultural, physical, biological and chemical methods have been tried to control it without much success. Moreover, the bacterial wilt resistant varieties of chilli are failing to control the disease due to unknown reason specific to the abovesaid part of Odisha. This study is targeted to find out the diversity among the various isolates, its survival and virulence factors as well as management which can be implicated in the farmer’s field. Here in the study five isolates were collected from the coastal vegetable belt of Odisha. All isolates were named as RS-1, RS-2, RS-3, RS-4 and RS-5 respectively. Further they were tested for the diversity studies which include morphological, cultural, biochemical as well as molecular variability among them. They all were tested in different growth media for the colony growth and found that TZC media and CPG media were the best media for the growth of the bacteria respectively. All are gram - ve isolates, starch hydrolysis -ve, catalase test +ve, oxidase test + and KOH test +ve. Based on carbohydrate utilization test it is found that the Ralstonia solanacearum belongs to race 1 biovar 3. From the host range studies, we came to know that all the hosts which are taken up produces same symptom across the plants. The virulent isolate produced swimming, swarming and twitching motility and produced EPS in the plates. To find out what is the correlation between weather parameter and disease incidence an experiment was designed to examine where significant positive correlation was observed for maximum temperature, minimum temperature, bright sunshine hours, morning humidity, rainfall and evaporation on wilting while evening relative humidity was negatively correlated. For the bacterial growth pH 6.5 and temperature 300 c is the most suitable. In the management practices we have taken from a wide range of botanicals to bioagents to chemicals. Among the botanicals, Neem leaf extract was found significantly superior than rest of the plant extracts. The antagonistic microorganism P. fluorescens showed maximum inhibition of the R. solanacearum which was found significantly superior over other treatments. Among different chemicals and their combinations, streptocycline showed the highest inhibition followed by copper oxychloride. Integration of different amendments and bioagents to manage the disease revealed that combination Neem cake + T. harzianum+ P. fluorescens+ Streptocycline + Copper oxychloride resulted lowest wilt incidence.EnglishThesis