Interaction between Biotic and Abiotic Agents to Control of Potato Bacterial Wilt Disease

Bacterial wilt disease caused by Ralstonia solanacearum (Smith) Yabuuchi, et al. (1995) is one of the most important bacterial diseases over the world. This study was planned to control the disease using interaction between biotic and abiotic agents, under greenhouse experiment. In vitro, tested bactericides (gentamycin, ceflaxcin and copper sulphate) were decreased growth of R. solanacerum compared with control treatment. Copper sulphate was the most effective compared with ceflaxcin and gentamycin, but ceflaxcin was moderately effective and gentamycin was less effective against the pathogen. Inhibition zone diameter was increased with increasing concentrations of tested bactericides. Application of different bio-agent isolates (Pseudomonas fluorescence, Bacillus subtitlis, Bacillus megaterium and Serratia mareacescne) were reduced the growth of the pathogen compared with control treatment. B. subtilis isolate was the most effective, but isolates of Ps. fluorescens and B. megaterium were moderately effective and S. marescences isolate was less effective against the pathogen. Greenhouse experiments, disease severity were decreased and potato yield were increased with interaction between bio-agents (Bacillus subtilis, and Pseudomonas fluorescence isolates) and bactericides (gentamycin and ceflaxcin), or bio-agents and resistance inducers factors (salicylic acid and jasmonic acid) or bactericides and resistance inducers factors compared with control treatment. However, interaction between bio-agents as tuber treatment and bactericides as soil drench treatment or interactions between bactericides as soil drench treatment and resistance inducers as foliar treatment were the most effective against the disease and the yield. But, interactions between bio-agents as soil drench treatment and resistance inducers as foliar treatment were moderately effective to control the disease and the yield. But, interaction between ceflaxcin as bactericide and Ps. fluorescens isolate as bio-agent or salicylic acid as resistance inducer were the most effective on disease severity and the yield compared with other treatments, but interaction between B. subtilis isolate as bio-agent and jasmonic acid as resistance inducer were less effective compared with other treatment.