Biological control of tomato damping off caused by Sclerotium rolfsii
M Rajendraprasad, B Vidya Sagar, G Uma Devi and SR Koteswar Rao
In vitro evaluation was conducted with twenty four isolates representing twenty four isolates representing two different species Trichoderma harzianum and Trichoderma viride andtwelve different Baccillus subtilis and Pseudomonas fluorescence. These potential biocontrol agents were tested for their efficacy against phytopathogenicfungi Sclerotium rolfsii through dual culture technique. Therefore, these effective biocontrol agents can be used for greenhouse studies to confirm the feasibility of using in tomato damping off disease management. The combination of potential Trichoderma harzianum -1 and Pseudomonas fluorescence bacterial biocontrol agents (T5 and T6 treatments) also proved effective in increasing germination and to reduce pre and post emergence collar rot in the pots when inoculated with Sclerotium rolfsii. The treatments, T6 (seed treatment with Pseudomonas fluorescence-3 + soil application with Trichodermaharzianum -1) and T5 (seed treatment with Trichodermaharzianum -1 + soil application with Pseudomonas fluorescence-3) recorded 52.08 and 49.17 percent germination respectively when inoculated with Sclerotium rolfsii. The lowest incidence (47.92 percent) of pre emergence damping off was recorded in T6 (seed treatment with Pseudomonas fluorescence-3 + soil application with Trichodermaharzianum -1). Among the bio-control treatments the lowest (54.17 and 59.17) post emergence damping off incidence was recorded in T6 (seed treatment with Pseudomonas fluorescence-3 + soil application with Trichodermaharzianum -1) at 30 and 50 DAS. The combination Trichoderma harzianum -1and Pseudomonas fluorescence-3 biocontrol agents (T5and T6) treatment also proved effective in increasing the shoot and root weight and fresh and dry weight of tomato plants when inoculated with Sclerotium rolfsii.