Alternaria, fungicides, botanicals, poisoned food technique

Alternaria leaf blight caused by Alternaria brassicae is one of the destructive diseases of mustard and causes considerable loss in the yield and quality of the produce. An experiment was conducted in in vitro to evaluate the efficacy of five chemical fungicides at five different concentrations i.e. 50ppm, 100ppm, 250ppm, 500ppm and 1000ppm and five botanical extracts at three concentrations i.e. 5%, 10% and 15%, against Alternaria brassicae. The study was carried out using poisoned food technique for botanical extracts and chemical fungicides Completely Randomized Design (CRD). Among the fungicides Tebuconazole proved to be the most effective chemical fungicide recording 100% growth inhibition at all the tested concentrations which was followed by Mancozeb at 1000 ppm (96.05) and followed by Metalaxyl + Mancozeb at 1000ppm (92.10) whereas, 50 ppm chlorothalanil was least effective in reducing fungal growth(53.94). Among the botanical extracts, maximum inhibition (74.26%) of mycelial growth was observed in Turmeric at 15% concentration followed by 15% Veld grape (69.20%) and minimum inhibition percent (39.46%) was observed in Aloe vera at 5% concentration. The study indicated better performance of some chemical fungicides even at lower concentrations i.e. 100ppm and 250ppm. So, such effective fungicides could be used to minimize hazardous effect. Significant effect of some botanical extracts against pathogen growth suggests their application as potential control agent alternative to chemicals.