ABSTRACT

Chemical pesticides have disadvantages such as high production cost, short persistence, comparative low efficiency, development of resistance to toxin and causing ecological damage. In other to obtain better bio pesticides, Rhizopheric soils of turmeric plants were screened for the presence of Bacillus species which have antifungal tendencies against known fungal pathogens such as Aspergillus niger Rhizopus stolonifera, Penicillium species and Candida species. Four Bacillus isolates were identified as Bacillus subtilis, Bacillus cereus, Bacillus megaterium and Bacillus licheniformis. All the Bacillus isolates have inhibitory potentials with  Bacillus subtilis exhibiting the highest potentials. Therefore, Bacillus subtilis was chosen as the ideal organism for optimization studies on the conditions for antifungal activities. Its optimal pH was found to be at 6.0 and temperature at 40 0C, incubation time at 96 hours and the best carbon source was glucose. Hence, it is therefore obvious that a good manipulation of the growth conditions for B. subtilis culture maybe an avenue for sourcing adequate quantity of these antifungal agents for the control of fungal phytopathogens. It is therefore recommended that optimization studies be carried out on the growth of Bacillus specie itself.