Effect of certain rhizobacteria and antagonistic fungi on root-modulation and root-knot nematode disease of green gram

Abstract

Effect of soil application of rhizobacteria (Azotobacter chroococcum, Azospirillum lzpo/erum, Bacillus subtilis and Beijerinkia indica), antagonistic fungi (Arthrobotrys oligospora, Cylindrocmpon destructans, Verticillium cblamydosporium and Paecilomyces lilacinus) and fenamiphos on root nodulation, plant growth, biomass production and gall formation and reproduction of Meloidogyne incognita were investigated on green gram in field trails. Application of rhizobacteria resulted in a significant increase in the numbers of functional nodules (pink coloured) per root system of nematode inoculated or uninoculated plants; numbers of nonfunctional nodules (brown coloured and degenerated) were decreased. Application of the rhizobacteria significantly increased dry weight of shoots of uninoculated plants. Growth of nematode inoculated plants was enhanced due to application of rhizobacteria and P. lilacinus. Treatment with B. subtilis or B. indica reduced galling by 33-34% and increased the dry weight of shoots by 22-24%, respectively. Corresponding values for the nematicide (fenamiphosl were 43 and 14%, respectively. Egg mass production and soil populations of M. incognita were more adversely affected. Maximum decrease in the soil population, 84%, occurred due to A. ltpoferum.