| dc.description.abstract | Three Trichoderma spp. were isolated from agricultural soil in Embu district, Kenya and
identified morphologically as T. harzianum, T. polysporum and T. viride. These isolates
were evaluated for their effect on the growth of F. oxysporum var phaseoli. Evaluation of
the effect of Trichoderma spp. on F. oxysporum var phaseoli was carried out by setting
up invitro experiments and green house experiment. Invitro experiments were done by
placing 5mm mycelia growth disc cut out from the growing Trichoderma spp. isolates
and placed on one side of a 9 mm PDA plate, a similar disc of F. oxysporum var phaseoli
isolate was cut out and placed 3 mm opposite the Trichoderma spp. mycelia disc. F.
oxysporum var phaseoli without Trichoderma spp. was also cultured as a control; all the
treatments were in triplicates.
A green house experiment was carried out by planting common bean seeds coated with
Trichoderma spp. in sterilized soil infected with F. oxysporum var phaseoli. The beans
were immersed in a mixture of gum Arabic and Trichoderma spp. and left for 5 hours
prior to planting so as to let the mixture attach to seed coat. Seven mixtures of
Trichoderma isolates were formulated: T. polysporum; T. harzianum; T. viride and in
combinations of the species; T. polysporum and T. harzianum; T. polysporum and T.
viride; T. harzianum and T. viride; T. polysporum, T.harzianum and T.viride. The soil
was placed in 22cm diameter pots which were then applied with manure at a rate of; 0g
(control), 38g (without Trichoderma spp.) 38g, 28g, 18 g and 9 g (with Trichoderma
spp.). The same procedure was followed with NPK fertilizer application except that
fertilizer rates were; 0g (control), 0.76g (without Trichoderma spp.), 0.76 g, 0.57 g, 0.38
g, 0.19 g (with Trichoderma spp.).
Invitro experiments of F. oxysporum var. phaseoli with T. harziunum, T. polysporum or
T. viride revealed that each of these Trichoderma species inhibited growth of the
pathogenic fungi. T. polysporum had the highest inhibitory (P<0.05) effect at 64% while
T.viride had the least inhibitory effect (47%). On the other hand a combination of manure
and the Trichoderma species improved growth of common bean when grown in F
showed a highly significant effects (P<0.001) on all the bean growth parameters
measured. The combination of Trichoderma spp. and fertilizers however did not show
significant difference (P>0.05) among the different rates of fertilizer in root length and
fresh weight. The results reveal the ability of Trichoderma spp. to control pathogens and
improve plant growth | en |
