Evaluation the Effect of Fungicides, Micronutrients and Botanicals on Purple Blotch Complex of Onion in Bangladesh

Field research was conducted in the central research farm of Sher-e-Bangla Agricultural University (SAU), during the period from October 2020 to March 2021. The experiment was a layout with RCBD design to evaluate the effect of selected fungicides (Indofil, Mancer, and Ridomil Gold), micronutrients (Zinc, Boron, and Magnesium), and botanicals (neem and eucalyptus leave extract) on purple blotch complex of onion. Data were collected on percent disease incidence and percent disease index, the number of leaves per plant, leaf length, bulb diameter, bulb weight (fresh and dry), and yield. The local cultivar Faridpuri was used as a tested variety. Among the selected fungicides, Ridomil Gold gave a better result than other fungicides in controlling the percent disease incidence (52.67%) and percent disease index (49.00%) with the highest number of yield qualities per plant. In addition to this, the highest bulb diameter (18.23 cm), single bulb weight (47.98 g), fresh weight (3.16 Kg/plot), and dry weight (2.88Kg/plot) were also obtained in Ridomil Gold treated plots. This treatment also gave better yield performance (9.60 t ha-1) followed by Indofil (8.20 t ha-1) and Mancer (7.90 t ha-1), and increased yield by 54.34% over the control treatment. From the study, it was also found that among the micronutrients, boron gave more satisfactory results than botanicals.