Evaluation of some fungi and bacteria for biocontrol of anthracnose disease of cowpea

The efficacy of some fungal and bacterial isolates obtained from cowpea phylloplane in inhibiting the in vitro and in vivo growth of Colletotrichum lindemuthianum, causal agent of anthracnose of cowpea was investigated. Inhibition of growth of the pathogen with production of zones of inhibition was observed for Aspergillus flavus, A. ochraceus, Penicillium aurantiogriseum, Bacillus subtilis-BS21, B. subtilis-BS22 and B. subtilis-BS23. Inhibition of growth on contact was recorded for A. niger while Trichoderma viride-TH14 and T. viride-TH31 hyperparasitized the pathogen. The two isolates of T viride and all tested bacteria significantly reduced seedling infection from anthracnose infested seeds in pot experiments. Spray application of T viride-TH31 on inoculated cowpea plants in the field effectively suppressed the incidence and severity of anthracnose disease, and significantly increased yield over the control. The antagonist was more effective when applied twice weekly than once in a week.