The antifungal activity of the methanolic extracts prepared from 11 plant
species (mentioned in part A) was screened against 9 plant pathogenic fungi
(Alternaria alternata. Aspergillus flavus. Botrytis cinerea, Fusarium oxysporum,
Fusarium solanl, Rhizoctonia solani, Sclerotinle sativa, Sclerotium batelicola and
Sclerotium rolfs;'). Each plant extract was tested at five concentrations, namely 0, 10,
20, 30 and 40%. Thymus vulgaris extract showed the highest Inhibitory effects on the
culture growth of all tested fungi. This extract reduced the fungal dry weights by 42 to
96%. It had t he lowest values 0 f the minimum I nhibitory concentration that inhibits
50% (MICso) and 90% (MIC90) for all fungi. A. altemata, A. tlevus and S. bataUcola
were the most persistent fungi against all methanolic plant extracts tested. Their
growth was even promoted by most of the plant extracts. Among the Rlant extracts
tested, Nigella sativa extract was the most effective one in inhibiting the spore
germination of all tested fungi by 79 to 98%. In descending order, the extract of T.
vulgaris was the second in terms of its capability of inhibition against fungal spore
germination. In greenhouse experiments, the plant extract of N. sativa was the most
effective one in the management of the damping-off disease caused by·F. solani and
S. sativa on cowpea plants giving 93% control. The extract of Ricinus communis gave
the highest level of controlling the damping-off disease caused by F. sofani (93%
control).