Weed management strategies for rapeseed-mustard in Jammu and Kashmir, Uttarakhand and Himachal Pradesh: A comprehensive review

Rapeseed-mustard is a major edible oilseed crops in India. Advancements in rapeseed-mustard production technology have led to significant productivity gains. However, various biotic stresses, particularly weed infestations, continue to pose substantial challenges, with potential yield losses reaching up to 45%. They lower the crop productivity and quality by competing with crop plants for available nutrients, water, and light while also affecting the agro-ecosystem. Numerous weed species impact these; however, the degree of yield and resource depletion is location-specific. Many weeds are specific to certain crops or locations. Orobanche aegyptiaca is increasingly prevalent in rainfed areas of Rajasthan, Haryana and Madhya Pradesh while Chenopodium, Asphodelus, Melilotus and Trianthema species are associated with yield reductions in other regions. The Himalayan region states such as Jammu and Kashmir, Himachal Pradesh and Uttarakhand account for a very small share of India's total rapeseed mustard output nonetheless the crop plays a major local role in crop diversification and is quite vital for edible oil self-reliance in these states. The crop in the hill states of Jammu and Kashmir, Himachal Pradesh and Uttarakhand experiences significant weed infestations predominantly by broad leaved species such as Chenopodium album, Melilotus indica, Anagallis arvensis, Vicia sativa, grassy weeds Phalaris minor, Avena fatua and sedges Cyperus rotundus. Rapeseed-mustard is particularly vulnerable to weed competition during the first 20-40 DAS, comparatively more than other oilseed crops. The weed management in rapeseed-mustard is carried out both by cultural and herbicidal approaches. Henceforth, the application of herbicides at critical growth stages along with one or two hand weeding at appropriate intervals poses a significant suppressing effect on weeds and boosts the crop yield. The economic analysis of several studies has concluded that fluchloralin and pendimethalin alone or in combination with hand weeding at 30 DAS is most economical to suppress weeds.