Tropical and subtropical agroecosystems
On-line version ISSN 1870-0462
WEPUHKHULU, Miriam et al. Effect of soil fertility management practices and Bacillus subtilis on plant parasitic nematodes associated with common bean, Phaseolus vulgaris. Trop. subtrop. agroecosyt [online]. 2011, vol.13, n.1, pp. 27-34. ISSN 1870-0462.
On-farm and on-station field experiments were carried out to determine the potential of combining Bacillus subtilis with soil fertility management practices for controlling plant parasitic nematodes associated with common bean, (Phaseolus vulgaris). The treatments were Bacillus subtilis (isolate K194), B. subtilis plus cow manure, B. subtilis plus mavuno, Bacillus subtilis plus calcium ammonium nitrate + tripple super phosphate, manure alone, mavuno alone with calcium ammonium nitrate + tripple super phosphate as the control. The recommended 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 inoculum 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 produced galls with galling indices 1.6 and 4.5 respectively 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 diversity. It can 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.
Keywords : Diversity; inorganic fertilizers; organic amendments; biological control.