Disease control strategies for Knol-Khol: Bio-agents, botanicals, and chemical fungicides

Abstract

Knol-Khol (Brassica oleracea var. gongylodes L.) is a Brassicaceae family cold-season crop planted mostly for its tasty knob. It is widely farmed in Jammu and Kashmir, West Bengal, Maharashtra, Assam, Uttar Pradesh, Punjab, Odisha, and areas of South India under the names Khol rabi, Navakol, and Ganthgobhi (Mishra et al., 2012). The study sought to elucidate crucial characteristics of Knol-Khol's downy mildew and its management through the use of chemicals, bio-control agents, and botanical treatments. The most effective treatment involved two foliar sprays of Metalaxyl + Mancozeb (0.25%), followed by Azoxystrobin (0.1%) with a disease intensity of 18.32% and a yield of 202.23 q/ha, compared to the control's 54.29% disease intensity and 140.73 q/ha yield. Trichoderma viride (@ 0.6%) had the lowest disease intensity (32.38%) and yield of 174.20 q/ha when compared to the control. Metalaxyl + Mancozeb > Azoxystrobin > Mancozeb > Propiconazole > Copper oxychloride > Trichoderma viride > Trichoderma harzianum > Pseudomonas fluorescence > Neem > control was the order of efficacy and yield.