Aqueous plant extracts of Allium cepe (bulbs), A. sstivum (cloves), Artemisia
judaica (leaves and flowers), Carum csrvi (seeds), Datura stramonium (seeds), Eruea
sativa (seeds), Eucalyptus g/obulus (fresh leaves), Mentha viridis (leaves), Nigella
sativa (seeds), Ricinus communis (seeds) and Thymus vulgaris (leaves), used at
concentrations of 0, 10, 20, 30 and 40%, were evaluated in vilro for there ailelopathic
effects on mycelial growth and spore germination of nine plant pathogenic fungi i. e.,
Alternaria alternata, Aspergillus ttevus, Botrytis cinerea, Fusarium oxysporum,
Fusarium soteni, Rhizocton;a so/ani, Sclerolinia sativa, Sclerotium batatico/a and
Sclerotium rolfsii. The extracts enhibited the fungal growth of the tested funQ!_ at
variable degrees. A. setivum extract showed the greatest inhibitory effects on mycelial
growth and spore germination of all tested fungi. It inhibited the spore germination by
95 to 99% and decreased the tungal dry weight by 56 to 91%. D. stramonium and N.
sativa extracts induced a significant reduction in the fungal dry weights when
compared to the other plant extracts. The extracts of A. setivum and E. sativa showed
the highest inhibitory effect on the spore germination. A concentration of 10% of
these extracts prevented the germination of 90% of the spores of these fungi. In
greenhouse experiments. all tested plant extracts caused significant protection of
cowpea seeds against the infection by the soil-borne fungi, .whereas the extract of D.
stramonium produced 100% control of the cowpea damping'off caused by F.
oxysporum while 93% control of the cowpea damping-off caused by F. solanl was
obtained when A. sativum extract was used.