Inhibitory effect of botanicals on growth and sporulation of Fusarium oxysporum inciting wilt of Chilli (Capsicum annuum L.)

Abstract

The antifungal activity of twelve botanicals including commercial formulations of neem and garlic at 1, 2, 5 and 10% concentrations was tested against Fusarium oxysporum (i.e., Isolate Fo8) under in vitro conditions. The botanicals revealed marked reduction in mycelial growth and sporulation of the F. oxysporum isolate. Growth inhibition of F. oxysporum increased linearly with an increase in concentration of the botanicals. Among the botanicals, neem oil formulation (Nemazal) and garlic oil exhibited significant effect on the test fungus. The neem oil (Nemazal) and garlic oil at 10 per cent concentration completely inhibited the mycelial growth that was followed by mustard oil (69.26%), Datura (46.67%), Withania somnifera (34.44%), whereas, the effectiveness of rest of the leaf extracts viz., Chrysanthemum (30.37%), Duranta erecta (28.15%), Bougainvillea (26.30%), Clerodendron enerme (24.44%), Parthenium (20.37%), Cannabis sativa (18.52%) and Eucalyptus (16.30%) thereby indicating less effectiveness. Garlic oil was highly effective (100%) even at 5 per cent concentration, whereas, neem oil was comparatively less effective (59.63%). Similarly, complete inhibition in sporulation was observed by the use of neem oil and garlic oil at 10 per cent that were statistically at par to mustard oil (93.75%), Datura (90.94%), Withania somnifera (87.50%), whereas, the effectiveness of rest of the botanicals viz., Chrysanthemum, Duranta erecta, Bougainvillea, Clerodendron enerme, Parthenium, Cannabis sativa and Eucalyptus varied between 12.82 to 70.00 per cent. The rate of sporulation of F. oxysporum decreased linearly with an increase in concentration and the type of botanicals.