ISOLATION, CHARACTERIZATION AND MANAGEMENT OF ALTERNARIA LEAF BLIGHT OF TURNIP THROUGH BOTANICALS

Abstract

Turnip is an important winter vegetable. Worldwide there are several fungal pathogens that cause leaf blight diseases on wide range of host plants including turnip. The isolated fungus from infected leaves were identified microscopically for morphological characterization and genetically by the nucleotide sequencing of amplified ITS1/ITS4 and BT2a/BT2b region of rDNA and identified fungus was found to be Alternaria brassicicola. Due to their reduced side effects, superior biodegradability, and lower toxicity when compared to other synthetic fungicides, natural compounds have recently received significant interest as an alternative to synthetic fungicides. Aqueous solutions of weed Flora like, Solanum nigrum, Nicotiana plumbaginifolia, Trianthema portulacastrum, Malvestrum coromendelianum, Chenopodium album, and Parthenium hysterophorus were tested against target pathogen. Chenopodium album concentrations in control exhibit maximum growth up to 75.67mm while in concentrations of 250, 500 and 1000ppm lessen growth up to 13.00, 12.33, and 00.00 mm. While Solanum nigrum against A. brassicicola at 250, 500 and 1000 ppm concentrations show reduction in fungal growth up to 29.67, 15.33, and 00.00 mm. While using Nicotiana plumbaginifolia against target pathogen in concentration of 250, 500 and 1000 ppm minimize growth up to 24.00, 18.33, and 00.00 mm. Chenopodium album, Solanum nigrum and Nicotiana plumbaginifolia give better results against A. brassicicola. Therefore, biological control is an excellent and safe approach to control fungal pathogens and to provide less chemical usage.