Comparative Effects of Culture Filtrate of Soil-Borne Fungi on Mortality and Infectivity of Juveniles of Meloidogyne incognita

Culture filtrates of Aspergillus niger, Pythium debarianum, Fusarium oxysporum f. sp. Iycopersici, F. solani and F. moniliforme were studied in vitro to see their influence on mortality of second stage juveniles (J₂) of the root-knot nematode, Meloidogyne incognita. The A. niger and F. moniliforme filtrates were also evaluated by bare root dip technique for their biocontrol potential against M. incognita on tomato under greenhouse conditions. The data clearly established that culture filtrates of A. niger were the most effective against J₂ followed by F. moniliforme, F. solani, F. oxysporum and P. debarianum. However, this effect varied according to the type of growing media, filtrate dilutions and time of exposure. Pre-inoculation root dip treatment with culture filtrates of A. niger or F. moniliforme significantly reduced gall formation and enhanced plant growth. The best efficacy was obtained from PD broth medium than that resulted from CD broth. The nematicidal activity of root dip treatment with either A. niger or F. moniliforme grown on PD broth for 20 min was significantly similar to that of the standard nematicide, oxamyl.