In vitro Efficacy of Fungicides and Bioagents against Early Blight of Tomato caused by Alternaria solani

In vitro evaluation of three contact and five systemic and two combination was carried out under laboratory condition in 2018-19 at Department of Plant Pathology, College of Horticulture, Mysuru by using Potato Dextrose Agar medium (PDA) as basal medium and six biocontrol agents were evaluated through dual culture technique. The result revealed that, there was significant difference among the fungicides in inhibiting the radial growth of the A. solani. Among the different contact fungicides evaluated against test fungi the least mean per cent inhibition of 78.61% was recorded in Mancozeb75%WP and it was found significantly superior over other two fungicides. The least per cent inhibition was noticed in case of Mandipropamid 23.4% SC which has recorded 18.80% inhibition. Among the five systemic and two combination fungicides evaluated against A. solani, Hexaconazole @ 0.1% and 0.15% has recorded maximum inhibition of mycelial growth of test fungi and which has recorded 86.22% inhibition followed by 85.00% inhibition was recorded in Trifloxystrobin 25 + Tebuconazole 50% WG @ 0.15% . The least percent inhibition of 53.99% was recorded in Pyraclostrobin 20%WG @ 0.05%. The results also indicated that the per cent inhibition was increased by increasing the concentration of fungicides tested. Among the different antagonistic organisms evaluated maximum inhibition of mycelial growth of A. solani was recorded in Trichoderma asperellum (69.69 %) followed by Trichoderma harzianum (67.51%). Among the four bacterial bio agents Bacillus vezelensis has recorded 62.76 % inhibition followed by Pseudomonas putida (43.13%) and the least per cent inhibition of mycelial growth was noticed in Pseudomonas fluorescens (42.19%) at 5 Days after incubation.