Vol. 11, Special Issue 4 (2022)

Author(s):
Manthesha HD, Mallikarjun Kenganal, Yenjerappa ST, Aswathanarayana DS and Vikas Kulkarni

Abstract:
Onion (Allium cepa L) cultivation has been hampered by many pests and diseases. In recent times onion twister has become most serious and threatening since two years. The severity of disease witnessed drastic decline in production and shortage in domestic supply across the country. Its management was studied using different fungicides along with bio-control agents Trichoderma and Pseudomonas in combined mixture form during Rabi 2021. The experiment was conducted on a site previously cultivated with onion and infested by sever twister disease. Among the different treatments, folair application of carbendazim 12% + mancozeb 63% 75 WP at 2.5g/l (T₉), Trichoderma + Pseudomonas mixture at 10 g/l concentration (T₁₃) and propiconazole 25 EC at 1 ml/l (T₁₀) recorded less PDI of 16.59, 17.26 and 18.54 respectively. Maximum PDI of 72.11 was observed in control plot. The yield was also significantly superior in T₉ with yield of 28.28 t/ha and B:C value of 5.74 followed by T₁₀ which had yield of 27.45 t/ha and B:C ratio of 5.59 and T₁₃ with an yield of 26.89 t/ha and B:C ratio of 5.46. Lowest yield (14.70 t/ha) was recorded in control which had B:C ratio of 3.03. It was necessary that among these best fungicides or bio-control agents’ mixture, any one shall be adopted but spraying of three times at an interval of 15 days in essential once the symptoms are first observed for effective control of the disease.