Control of Bacterial Wilt (Ralstonia solanacearum) and Reduction of Ginger Yield Loss through Integrated Management Methods in Southwestern Ethiopia

Abstract

Background: Bacterial wilt incited by Ralstonia solanacearum is the most important disease affecting ginger production in southwestern Ethiopia. The unavailability of disease-free planting materials, resistant cultivars, and effective chemical compounds are the key constraints in managing the disease. Objective: The study was initiated to determine the effect of integrated management methods on bacterial wilt disease and yield loss of ginger through combining hot water, bio-fumigation, soil-solarization and chemical pesticides. Methods: A total of seven treatment combinations comprising hot water, bio-fumigation, soil-solarization, Mancozeb, and bleaching powder were tested in a randomized complete block design in three replications. Data on disease incidence, growth, yield, and yield components were recorded from randomly selected plants. Results: The use of Mancozeb for seed socking and soil drenching combined with bio-fumigation and soil-solarization reduced the incidence of bacterial wilt by 63.3% and enhanced the rhizome yield by 66.8%. Rhizome and soil treatment using bleaching powder along with soil bio-fumigation also reduced the disease incidence by 38.9% and increased ginger yield by 61.5%. It also provided the highest (6678.7%) marginal rate of return of any treatment combination tested in the experiment. Disease incidence was highly significantly and inversely (r= -0.98**) correlated with rhizome yield. The regression slope estimated that 83.4% of ginger yield loss was associated with bacterial wilt disease. Conclusion: A combined application of Mancozeb, bio-fumigation and soil-solarization can be used to control ginger bacterial wilt. Alternatively, bleaching powder for rhizome and soil treatment in conjunction with bio-fumigation can be employed as an integrated management system against the disease.