Integrated weed management in menthol mint (Mentha arvensis L.)

Man Singh; Aparbal Singh; Kothari, S. K.; Verma, B. S.; Singh, D. V.

Field experiments were conducted at the CIMAP research farm, Lucknow in Uttar Pradesh, India during 1991-92 to study the efficacy of the application of pre-emergence herbicides (pendimethalin at 1.0 kg/ha, oxyfluorfen at 0.25 kg/ha, diuron at 0.4 kg/ha), alone and in combination with post-emergence application of fluazifop butyl 0.25 kg/ha just after first harvest, organic mulch (paddy straw 7.5 t/ha) at 35 days after planting (DAP) or of weeding + organic mulch at 65 DAP compared with one weeding + organic mulch, unweeded and weed-free control on weed competition, herb and oil yield of menthol mint (Mentha arvensis). Uncontrolled weed growth caused 78 and 81% reduction in total (I + II harvest) herb and oil yield, respectively. The reduction in herb and oil yield in second harvest was 92 and 93% against 70 and 73% in the first harvest, respectively, indicating higher susceptibility of menthol mint to weed interference during later period of its growth. All the weed control treatments gave desired weed control in the first harvest by reducing weed dry biomass by more than 80%. However, during second harvest, only the pre-emergence herbicides in combination with organic mulch (paddy straw 7.5 t/ha) at 35 days after planting (DAP) or weeding + mulching at 65 DAP registered more than 90% weed control efficiency and produced herb and oil yield at par to weed-free control. Application of organic mulch at 35 DAP, following pre-emergence application of any of the above herbicides, is suggested for effective and economical weed management in menthol mint.