Evaluation of bio formulations against Colletotrichum truncatum and Macrophomina phaseolina in soybean

Soybean crop is known to be infected by several seed and soil borne pathogens affecting the seed quality and viability in field and during storage. Colletotrichum truncatum and Macrophomina phaseolina are the important seed and seedling pathogens affect the germinating seed. Since intensive use of synthetic pesticides is unsafe, bio formulations can be an alternative as they are eco-friendly and sustainable without any residual effects. Thirteen commercially available bio formulations were evaluated for their antagonistic activity against these two test pathogens. The population density of the bio agents ranged from 1×105 to 6x 108 cfu/g.The dual culture assay of C.truncatum and M. phaseolina revealed that, highest per cent inhibition was recorded by formulation T5, T. viride + P. flourescens followed by T6, T. harzianum+ B.subtilis with88.16% and 88.01%; 62.00% and 53.64 per inhibition of mycelial growth, respectively. The fungal bio agents T.viride and T.harzianum were found effective over the bacterial bio agents P.fluorescens and B. subtilis for their suppressing activity. However, the bio fertilizer, Rhizobium sp. was least effective with 72.92% and 32.73% mycelial inhibition of both the pathogens, respectively.While, the formulation T10 basil oil @ 5ml/l was observed equally effective as that of fungicidal check carboxin+thiram @3g/l in poisoned food technique in suppressing cent per cent mycelial growth of both the test pathogens. However, the formulations T8 biopolymer and T9 neem oil were least effective with (21.18%, 2.32%) and (23.66%, 10.44%) inhibition, respectively.The response of these bio formulations for seed quality and seed health against C. truncatum stated that seed treatment formulation T5, T. viride + P. flourescens @10g/kg was most effective with 85.50 per cent seed germination followed by T10basil oil @5 ml/kg with 84.50 per centwhich were statistically on par with each other. T5 has shown 34.79% increase of seed germination over untreated control (55.75%). Formulation T10 basil oil has recorded minimum 9.75% seed infection, maximum SV-I and SV-II (2355, 98 g) respectively. All the bio formulations except for T8 bio polymer and T13 GA3 have showed per cent seed germination above IMSCS against M. phaseolina. Formulation T5 has recorded highest 85.75 % seed germination and was on par with T10 basil oil, 85.00 per cent. However, T5 has exhibited 33.81% increase of seed germination over the control (56.75%). Seed treatment with T10 has reported minimum 7.00% seed infection followed by T5 with 8.00 per cent. Significantly highest 2190, 96.61g SVI-I and SVI- II, respectively was observed in T5. However, formulations, T8 biopolymer and T13 GA3 have showed maximum (27.25%, 24.00%) seed infection, lowest 1068, 48.62g, 1125, 55.14g, SV-I and SV-II, respectively. The results of the present investigation states that formulations, T5 T. viride + P. fluorescens, T1 10 and T6 T. harzianum+ B.subtilis were found effective for their antagonistic potential against C.truncatum and M. phaseolina.