Bioefficacy of sweet flag (Acorus calamus) against Ralstonia solanacearum causing bacterial wilt in solanaceous vegetable crops

Investigations were carried out to evaluate the bioefficacy of Sweet flag (Acorus calamus L.) against Ralstonia solanacearum (Smith) Yabuuchi et al – an incitant of bacterial wilt of solanaceous vegetable crops. TZC medium

amended with different concentrations of dried rhizome powder and its crude aqueous extract showed strongest antibacterial activity. Dried rhizome powder above 0.75 per cent and aqueous extract at 400μgml⁻¹ and above concentrations caused complete inhibition in colony growth of bacterium. Extracts in organic solvents (petroleum ether, methanol and ethanol) were ineffective in arresting the growth of the bacterium. Experiment conducted in polyhouse against bacterial wilt of bell pepper, revealed that untreated seedling planted and drenched with aqueous extract of dried rhizome powder of A. calamus 24hr after transplanting and thereafter five seedling drench at weekly intervals coupled with soil application of dried rhizome powder at the rate of 2.5 per cent at 30 and 45 DAT resulted in more than 90 per cent control of bacterial wilt disease.