Differential response of weed species to herbicides in potato.
Field trials were conducted on sandy loam soil at Jalandhar during the autumn season of 1988 to study the responses of different weed species (Chenopodium album, Rumex sp., Poa annua, Melilotus indica, Cornopus didymus [Coronopus didymus], Cyperus rotundus and Spergula arvensis), in potatoes cv. JH-222, to herbicide applications (2.0 kg/ha alachlor, 0.75 kg metribuzin, 0.30 kg oxyfluorfen, 0.75 kg pendimethalin, 0.50 kg paraquat and 0.75 kg isoproturon). Weed control efficiency of different herbicide treatments ranged from 40 to 91% (the greatest weed control treatment resulted from metribuzin). The total dry weight of weeds as a result of herbicide treatments ranged from 39.5 to 257.5 g/m2, compared with 428.3 g/m2 for the unweeded control and 82.0 g/m2 for weeding and earthing up. Total tuber yield for the crop as a result of herbicide treatment was 19.68-28.65 t/ha (the best treatment resulting from metribuzin), compared with 14.86 t/ha for the weedy control and 25.42 t/ha for weeding and earthing up.