Nematicidal Activity of Marine Sponge <I>Callyspongia diffusa</I> Associated <I>Pseudomonas fluorescens</I> BCPBMS-1

Abstract

Investigation carried out to study the nematicidal activity of marine sponge callyspongia diffusa associated Pseudomonas fluorescens BCPBMS-1. P. fluorescens strain was tested for nematicidal activity against Meloidogyne javanica which cause root-knot disease in green gram plant. The numbers of dead juveniles were counted up to 48 hrs at 12 h interval. Pot experiment was also done to check its ability in field. At the end of 48 hrs 90% of juveniles of M. javanica tested were found killed. About 3 kg of sterile sandy loam soil was filled in 6 pots and all of them were infected with 20 ml of M. javanica containing 1000 larvae (i.e.,) 50 larvae/mL. In infected plant chlorophyll-a content was 0.01mg/g on 5 th day, on 10 th and 15 th day it was totally absent. In treated plants, chlorophyll-a content was 0.49 mg/g on 5 th day, 1.3 mg/g on 10 th day and 1.42 mg/g at 15 th day. Chlorophyll-b was totally absent in infected plant at 5 th , 10 th and 15 th days. In treated plants chlorophyll- b content on 5 th day was 0.48 mg/g, it was 0.6 mg/g on 10 th day and 0.75 mg/g on 15 th day. In control plants on 5 th day it was 0.9 mg/g, 0.92 mg/g on 10 th day and 1.0mg/g on 15 th day. Total protein content of the infected plant was 0.1mg/g on 5 th day, it was below detectable level on 10 th and 15 th days. In treated plants, total protein content was 2.3mg/g on 5 th day, 4.3mg/g on 10 th day and 15 th day it was 7.2 mg/g. The obtained results of this study confirmed that Pseudomonas fluorescens BCPBMS-1 is a promising nematicidal agent and great potential in Meloidogyne javanica management in green gram plant.