Response of oat (Avena sativa) varieties and wild radish (Raphanus raphanistrum) to thifensulfuron plus tribenuron

Field studies evaluated wild radish control in oat with thifensulfuron plus tribenuron in 1995 and 1997. Thifensulfuron plus tribenuron at 16 or 21 g ai/ha controlled wild radish completely in both years. In tolerance studies conducted in 1995 and 1996, thifensulfuron plus tribenuron reduced vigor o f 'Bay,' 'Belle,' 'Dane,' 'Ensiler,' 'Gem,' 'Horicon,' 'Ogle,' 'Porter,' an d 'Prairie' oat varieties and Wisconsin test selection oat 'X6396-1' up to 25% 7 d after treatment(DAT), but all chlorotic symptoms had disappeared 28 DAT. Thifensulfuron plus tribenuron reduced oat height 13 to 19% in 1995 a nd 21 to 24% in 1996 7 DAT. Bay, Belie, Dane, Ensiler, Horicon, Prairie, an d X6396-1 recovered from height reductions by 28 DAT in 1995; however, in 1 996 only Horicon and Porter recovered. Thifensulfuron plus tribenuron did n ot reduce 1995 grain yields, but 1996 Bay and Porter grain yields were redu ced 29 and 15%, respectively. Dome and Prairie seed weights were reduced 7 and 14%, respectively, in 1995, whereas no seed weight reduction occurred i n 1996.