Fusarium yellows is a disease of common beans (
Phaseolus vulgaris
,L.) caused by
Fusarium oxysporum
Schl. F. sp
phaseoli , it has been found to be important in Busia district of Western province, Kenya. The study on fungitoxic properties of four locally available crude plant extracts was aimed at evaluating their efficacy in controlling
Fusarium yellows infestation under the field conditions. Crude plant extracts from
Azadirachta indica
,
Tagetes minuta
,
Nicotiana tobacum
and
Vinca rosea
were tested against
Fusarium oxysporum Schl. F. sp.
phaseoli. Participatory On-Farm Trials (POFT) in six (6) divisions were carried out in August-September 2005 and March-June 2006; a total of thirty (30) farms were randomly surveyed. Minimum Inhibitory Concentration (MIC) of crude plant extracts against
Fusarium was determined by broth microdilution method. Analysis of variance (ANOVA) was performed on the data, using Genstat 8th edition statistical program (Release 8.11, Lawes Agricultural Trust, Rothamsted Experimental Station, Harpenden, UK). Means were separated using LSD. Crude plant extracts exhibited fungitoxic activity against
Fusarium oxysporum Schl. F. sp.
phaseoli, with varying degree of efficacy.
Nicotiana tobacum and
Vinca rosea were not effective,
Azadirachta indica and
Tagetes minuta exhibited significant control over
Fusarium.
Azadirachta indica performed better amongst all the plant extracts. Common bean treatment with Benomyl 1 significantly reduced (P≤0.05) wiltincidence and increased growth in comparison to negative (–ve) control.
Azadirachta indica formulation gave a significant reduction in wilt incidence compared to the other three crude plant extracts formulations. It reduced the wilt incidence by 17.24% in comparison to
Tagetes minuta,
Nicotiana tobacum and
Vinca rosea whose wilt incidence reduction ranged from 5.84-9.8%.
Azadirachta indica inhibited
Fusarium growth at lower dosage than
Tagetes minuta,
Nicotiana tobacum and
Vinca rosea. Extracts from
Azadirachta indica and
Tagetes minuta are effective, cheap and ecofriendly promising methods for protecting common bean against
Fusarium oxysporum Schl. F. sp.
phaseoli.
