Ajayi, A.M

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This study was carried out to evaluate the efficacy of Allium sativum (garlic) crude extract and Trichoderma asperellum against cowpea anthracnose pathogen (Colletotrichum lindemuthianum). Three concentrations of garlic crude extracts were evaluated in-vitro using the food poison method in a Potato Dextrose Agar growth medium, while three-time interval of T. asperellum inoculation was undertaken before the introduction of the cowpea pathogen and evaluated using the dual culture technique. The in-vivo experiment involved prophylactic foliar spray of the most promising concentrations of garlic crude extracts and conidia suspensions of Trichoderma from the in-vitro study on healthy cowpea plants. A total of seven treatments (35% and 45% garlic crude extracts, 103 conidia/ml at 48 and 72 hrs. inoculation time, 106 conidia/ml at 48 and 72 hrs. inoculation time and the control, pathogen only) were evaluated in 21 plastic pots. The experiment was laid out in a Completely Randomized Design. The result shows that garlic crude extract at 45% concentration gave 100% inhibition of mycelia growth of C. lindemuthianum in-vitro. The lowest values for disease incidence (4.17 at three weeks after treatment) and the highest value for pod yield (10.33 pods) were recorded for T. asperellum at 106 conidia/ml at 72 hrs inoculation time. Garlic extract at 45% concentration gave 9.33 pods. Garlic extract and T. asperellum compared favourably in protecting cowpea against the attack of C. lindemuthianum. Consequently, both Garlic crude extract and T. asperellum are recommended as control agents for anthracnose disease of cowpea. Keywords: Allium sativum, Trichoderma asperellum, Colletotrichum lindemuthianum, Biological control, Pathogen