The study investigated the
in-vitro antifungal activities of sodium bicarbonate (NaHCO
3) and leaf
extracts of
Vernonia amydgalina
(bitter leaf) and
Azadirachta indica
(neem) on fungal species isolated from two cowpea
cultivars; IFE BROWN and Drum (a local cultivar). Concentrations of 1.95 mg/ml and 1.43 mg/ml were used for
A. indica
while 1.45 mg/ml and 1.15 mg/ml were used for
V. amydgalina. Sodium bicarbonate was evaluated on all the isolates at
2.0 mg/ml and 3.0 mg/ml. The inhibitory effects of these antifungal agents were compared with benlate (a synthetic
fungicide) on Potato Dextrose Agar. Benlate totally inhibited all the fungal isolates.
Candida
species isolated from the
two cowpea cultivars were greatly inhibited by the antifungal agents while
Trichoderma
species isolated from IFE
BROWN was the least inhibited. The inhibitory effects of NaHCO
3 and
A. indica on
Candida spp. were not significantly
different and values ranged from 74.5% to 84%. The two concentrations of
A. indica had better inhibitory effect on
Pythium
spp. than NaHCO
3.
Vernonia amydgalina at 1.45 mg/ml inhibited
A. niger
and
Candida spp. by 83.75% and
87.5% respectively while NaHCO
3 at 2.0 mg/ml inhibited
Rhizopus stolonifer
isolated from Drum by 75%. The study
concludes that the two plant extracts and sodium bicarbonate had broad spectrum activities on fungal species and are
therefore recommended as alternatives to toxic and synthetic fungicides.
