The eff ectiveness of some antibiotic and chemical compounds for controlling bacterial wilt caused by Ralstonia solanacearum from marigold (Tagetes papula l.)

Abstract

The effectiveness of three antibiotic and chemical compounds in controlling wilt disease caused by Ralstonia solanacearum from Tagetes papula L. in vitro and in net-house conditions are evaluated. In vitro, these compounds were tested on 10 strains of R. solanacearum to find bacterial inhibiting effect at 72 hours after inoculation. From there, the compound of Streptomycin + Oxytetracycline has higher effect in inhibitting R. solanacearum strains than the other two compounds as Oxytetracyline hydrochloride + Gentamicin sulphate, or Oxolinic acid. Under net-house condition, the compound of Streptomycin + Oxytetracycline and two strains of R. solanacearum RM3 and RM4 with the least sensitive characteristic to this compound are tested to evaluate the effectiveness of disease controlling on marigold plants. Through 6, 10, 14, 18 days after infection, both treatments infected with separate strains of RM3 or RM4 after applied the Streptomycin + Oxytetracycline compound have showed satisfactory effect. The effectiveness of reducing bacterial wilt disease is high ranging from 46.7% to 57.2%. At the same time, when these results are compared with the treatments that only infected with RM3 or RM4, their AUDPC index is also decreased. In addition, their severity index is reduced while they compared with treatments only infected with RM3 or RM4. The compound of Streptomycin + Oxytetracycline has shown effective disease reduction in the prevention and treatment of bacterial wilt caused by R. solanacearum on marigold, and it can be selected as one of the preventive measures this disease.