APPLICATION OF BACILLUS SPECIES CULTURED ON DIFFERENT LOW COST ORGANIC SUBSTRATES FOR THE CONTROL OF ROOT-KNOT NEMATODE INFECTION ON OKRA (ABELMOSCHUS ESCULENTUS MOENCH)

Abstract

Low cost organic substrates such as rice grain, chickpea, wheat grains, rice husk, chickpea husk and wheat bran were used to culture Bacillus subtilis and B. firmus. Vegetative cell counts of both bacterial species generally increased on majority of substrates in initial 5 days and declined in subsequent incubation. Spore counts also increased with time but declined at 10th day. Bacterial species cultured on various substrates were inoculated in soil before sowing of okra in a pot culture experiment. The growth of okra plants was significantly increased in all substrates except chickpea husk, as compared to control. Root-knot nematode infection severity was measured in term of galls/ root system and egg masses/ root system. Both bacterial species showed varying effectiveness when grown on different organic substrates, but they controlled root-knot nematodes infection in okra in comparison to the control.