EFFECT OF SOIL FERTILITY MANAGEMENT PRACTICES AND BACILLUS SUBTILIS ON PLANT PARASITIC NEMATODES ASSOCIATED WITH COMMON BEAN

On-farm and on-station field experiments were carried out to determine the potential of combining Bacillus subtilis with soil fertility management practices on plant parasitic nematodes and growth of common bean (Phaseolus vulgaris). The treatments were Bacillus subtilis (isolate K194), B. subtilis plus cow manure, B. subtilis plus mavuno, Bacillus subtilis plus farmer practice, manure alone ,mavuno alone with farmer practice as the control. The farmers’ practice entailed application of tripple super phosphate and calcium ammoniun nitrate at the rate of 1000 and 890 kg/ha, respectively. Manure and mavuno were applied at the rate of 10 tons and 890 kg/ha, respectively. The on-farm trial was carried out in 12 different farms. The combination of Bacillus subtilis and cow manure led to a 54% reduction in numbers of plant parasitic nematodes, compared to the untreated control. Consequently, damage by root-knot nematodes was 1.6 and 4.5 in plots treated with the combination (B. subtilis and cow manure) and the untreated control, respectively. Compared to the other treatments, combining B. subtilis and organic amendments resulted in the highest nematode evenness diversity. It can be therefore be concluded that the plant parasitic nematodes associated with common bean can be maintained at levels below economic threshold using B. subtilis combined with cow manure, an integration which also demonstrated conservation of the nematode diversity.