Efficacies of Trichoderma viride, Rhizobium leguminosarum and the fungicide
Topsin M70% individually and/or their mixtures were tested in vitro and greenhouse conditions to
control damping-off and root rot diseases of pea plants (Pisum sativum L., cv. Master P) caused by
Rhizoctonia solani. The ability of tested Rhizobium leguminosarum and Trichodermia viride to exhibit
plant growth promoting rhizobacteria (PGPR)-properties including ability to solubilize-P and
production of IAA, as well as production of siderophores, hydrocyanic acid (HCN) and secretion of
cell-wall degrading enzymes (chitinase and protease) were investigated. Also, under in vitro conditions the
effect of Topsin M70% on growth of R. solani and T. viride, R. leguminosarum and their mixtures was
determined. The fungicide effective concentration was found to range from 10 to 50 ppm for R. solani
and T. viride mycelial growth being 83.30, 100, 76.08 and 100% at 40 and 50 ppm of Topsin M70%.
The same trend was obtained with R. leguminosarum that showed maximum tolerance at 40 and 50
ppm of Topsin M70% with the average of 52.19 and 59.85% inhibition over control, respectively.
Additionally, greenhouse conditions were conducted on sandy clay soil at Etay El Baroud Agricultural
Research Station, Beheria Government, Egypt to study the singly effect of seed soaking in T. viride,
R. leguminosarum or their mixtures with the soil drench fungicide in pots after sowing of pea cv.
Master P in concern. Significant decrease of damping-off and root rot of pea was obtained. Numbers
of survived plants, shoot length as well as, fresh and dry weight were recorded. The combined
treatments R. leguminosarum + Topsin M70%, T. viride + Topsin M70% and R. leguminosarum +
T. viride + Topsin M70% were the most effective ones resulting the least percentage of total dampingoff
and the highest percentage of healthy plants being 96.67 and100.00%, respectively. Seed treatment
with T. viride, R. leguminosarum and drenched fungicide individually or in mixture improved plant
growth as indicated by the increased growth parameters and the physiological activities
(phytosynthetic pigments, peroxidase and polyphenol oxidase), especially in combined treatments.
Peroxidase and polyphenol oxidase activities were increased in the different treatments- even, the
fungicide drench treatment. Reduction in total damping-off was positively correlated with both
peroxidase (R2 = 96.70, P ˂ 0.005) and polyphenol oxidase (R2 = 89.60, P ˂ 0.005) activities.