OBSERVATIONS ON THE NEMATICIDAL EFFECT OF FUSARIUM SOLANI ON THE ROOTKNOT NEMATODE MELOIDOGYNE JAVANICA
A. Zareen, I.A. Siddiqui, F. Aleem, M.J. Zaki, S. Shahid Shaukat
The effects of 10 strains of Fusarium solani on Meloidogyne javanica were tested in vitro and in controlled conditions. Culture filtrates of the strains varied with respect to parasitism on eggs and females of M. javanica and nematicidal activity in terms of juvenile mortality. Mortality in boiled culture filtrates was slightly lower than that caused by un-boiled filtrates, but substantial nematicidal activity was retained, pointing to the relative thermostability of the active principle(s) involved. Aqueous and ethyl acetate extracts of F. solani produced higher nematicidal activity than a hexane extract indicating that the active compound(s) were polar in nature. Conidial suspensions of F. solani strains Fs5, Fs9 and Fs10 used as soil drench significantly reduced nematode populations in soil and root-knot disease severity, resulting in enhanced growth of tomato plants. There was no significant difference among F. solani strains on shoot fresh weight. Strain Fs5 was frequently reisolated from surface sterilized tomato roots. When evaluated in a field test, strain Fs5, reduced M. javanica reproductive potential, promoting growth of tomato plants. However, root length and fresh root weights were slightly lower in Fs5-treated plants.