FLAX TOLERANCE TO THIFENSULFURON AND TRIBENURON

Field experiments were conducted in 1994 and 1995 at Morden, Manitoba to investigate the tolerance of NorLin flax and FP 967, a sulfonylurea -resistant flax cultivar, to thifensulfuron and tribenuron. Herbicides were foliarly applied at 0, 1.3, 3.8, 7.5, 15, and 30 g a.i. ha(-1). Thifensulfuron caused chlorosis, stunting, delayed flowering and matur ity in NorLin, but yields were unaffected. Tribenuron severely injured NorLin flax and reduced seed yields at doses as low as 1.3 g ha(-1). FP 967 exhibited good tolerance to foliar applications of thifensulfur on, but was injured by higher doses of tribenuron. This suggests that FP 967 is not completely cross-resistant to all sulfonylurea herbicide s.