Chemical control of complex weed flora in wheat.
Field trials were conducted at Haryana during 1985-86 and 1986-87 to study the relative efficacy of different herbicides (0.16-0.50 kg/ha 2,4-D, 0.34-1.02 kg isoproturon, 1.60 kg metoxuron and 1.40 kg methabenzthiazuron, the 1st two applied alone or in combination with each other) for the control of weeds (mainly Chenopodium album, Lathyrus aphaca, Vicia sativa and Phalaris minor) in wheat cv. WH-283, and the effects of these herbicides on wheat yield. Herbicides resulted in 38-86% control of weeds 60 d after sowing and 10-245 g/m2 dry weight of weeds at harvest, the greatest control being due to isoproturon + 2,4-D at 1.02 + 0.48 kg. Mean yields as a result of herbicide treatment were 3.44-4.89 t/ha (the best treatment resulting from 1 kg isoproturon), compared with 3.28 t in the weedy control. The combination of isoproturon + 2,4-D was found to reduce crop grain yield by causing malformations of the earheads; it is suggested that 2,4-D-tolerant varieties of wheat should be tested with this herbicide combination.