Effect of botanicals on Ralstonia solanacearum and bacterial wilt incidence in tomato

Abstract

Tomato is considered as the second most important vegetable crop in India and major constraint in its production is bacterial wilt caused by Ralstonia solanacearum. The management of the disease is difficult and the chemicals are least effective and are hazardous. Hence, an alternate method of control needs to be developed which is effective, cheap and eco friendly. The water extract from only two botanicals viz., Ocimum gratissimum and Tylophora asthmatica were effective in inhibiting the growth of Ralstonia solanacearum. O. gratissimum extract showed highest inhibition zone of 28.66 mm at 1:0 dilution and had inhibitory effect upto 1:10 dilution with 22.66 mm inhibition zone. Alcohol extract of O. gratissimum was the most effective in inhibiting the growth of R. solanacearum followed by C. gigentea, O. sanctum, T. asthmatica, N. sativa and R. graveolens. Alcohol extract Ocimum gratissimum was found more efficacious than O. sanctum in delaying the onset of wilt disease wherein 100 per cent wilt incidence was observed at 56 DAI.