Non-chemical Methods for Controlling Seedborne Fungi in Carrot with Special Reference to Alternaria Radicina

The objective of the work was to study the efficacy of carrot seed treatment with antagonistic microorganisms Clonostachys rosea, C. solani, and grapefruit extract (Biosept 33 SLTM). Seeds were artificially inoculated with Alternaria radicina spores prior to treatment. The presence of fungi, seed germination and vigour were determined in laboratory tests, whereas seedling emergence and health were determined in sand and soil assays. Clonostachys spp. and grapefruit extract significantly reduced seed infestation with A. radicina and improved seed germination capacity. At a lower concentration of ioculum, treatment with Clonostachys spp. increased percentage of healthy plants in sand assay. At a higher concentration of inoculum, treatment with Biosept 33 SLTM at 0.5% was more effective. Inoculation with pathogen and, in most cases, the following treatments, did not affect total plant emergence in a soil assay. However, pathogen affected significantly a percentage of healthy plants. Treatment with Biosept 33 SLTM at 0.5% as well as with C. rosea increased their numbers significantly at both concentrations of inoculum.