Suppression of Meloidogyne javanica by Pseudomonas aeruginosa and Bacillus subtilis in tomato

Abstract

The effects of two strains of Pseudomonas aeruginosa (IE-6 and Pa-7) and an isolate of Bacillus subtilis on egg hatching, mortality and infection of MeloidogYl7ejavanica in tomato roots was evaluated under laboratory, greenhouse and field conditions. Cell-free culture filtrates of the bacterial isolates significantly reduced egg hatching and caused mortality of second stage juveniles of M. javanica. Better biocontrol was observed in 15 day old seedlings as compared to 30 and 45 day old plants. Culture filtrates of P. aeruginosa strains IE-6 and Pa-7 resulted in activity similar to that caused by viable and dead cells of P. aeruginosa whereas activity of the culture filtrate of B. subtilis was greater compared to the dead cells. Introduction of rhizobacteria in the root zone gave better results than stem injection or foliar application. Under field conditions, the isolates also significantly reduced nematode population densities and subsequent gall formation due to M. javanica.