DP Mamkaa and VI Gwa
Potency of some plant extracts (Moringa oleifera and Vernonia amygdalina) using three concentrations of hot aqueous plant extracts (5 g/250 mL, 10 g/250 mL and 15 g/250 mL) in culture for inhibition of Aspergillus flavus and Botryodiplodia theobromae mycelial growth were carried out at the Biological Science Laboratory, Federal University, Dutsin-Ma, Katsina State, Nigeria. Cowpea seeds showing various symptoms of rot were collected from Dutsin-Ma, Darawa and Makera markets and taken to the laboratory for isolation and identification of fungal pathogens. A. flavus, B. theobromae, F. oxysporum, A. niger and Colletotrichum sp. were isolated, identified and characterized from the pure culture of the fungi. Pathogenicity tests carried out confirmed that the isolates were pathogenic on the healthy cowpea seeds. 5 mL of M. oleifera and V. amygdalina were each mixed with 15 mL of potato dextrose agar separately on petri dishes and the pathogens were inoculated in the plates and incubated for 4 days. Measurements of mycelial radial growths were undertaken at 1 day interval throughout the period of incubation. The results obtained showed that M. oleifera and V. amygdalina all posses antifungal compounds that inhibited the growth of A. flavus and B. theobromae at all the level of concentrations and throughout the period of incubation. There was a significant difference (P ≤ 0.05) among concentrations when V. amygdalina was used. There was, however, no significant difference (P ≤ 0.05) among concentrations when M. oleifera was used. Extract of V. amygdalina was considered more effective in managing A. flavus compared to M. oleifera. Both M. oleifera and V. amygdalina significantly differed (P ≤ 0.05) at all levels of concentrations in inhibiting the mycelial growth of B. theobromae. It is therefore concluded that both M. oleifera and V. amygdalina can be formulated at different concentrations and use in the management of A. flavus and B. theobromae of cowpea seeds.