Abstract: Field experiments were carried out during 1997 and 1998 in northern Greece to investigate the effects of tank mixing rimsulfuron and primisulfuron with atrazine or dicamba against johnsongrass in corn. Sequential applications, where the johnsongrass herbicides were applied 5 d after the broadleaf herbicides, were also evaluated. Rimsulfuron applied alone at 10 g ai/ha gave very good control (91%) of johnsongrass, which was significantly higher than that provided by 30 g ai/ha of primisulfuron (43%). Rimsulfuron applied in tank mixture with atrazine (1.0 kg ai/ha) or dicamba (0.28 kg ai/ha) gave 12 and 17% lower johnsongrass control, respectively, than of rimsulfuron applied alone, whereas the corresponding reduction for primisulfuron was 18 and 43%. Efficacy of rimsulfuron applied 5 d after the application of atrazine or dicamba was similar to that applied alone; however, this was not the case for primisulfuron, where reduced antagonism was observed compared to that produced by its tank mixture treatments. Again, primisulfuron was affected more by dicamba than by atrazine. Corn yield with rimsulfuron and primisulfuron applied alone was more than double that of the untreated control and similar to that of the weed-free control. Also, rimsulfuron applied with atrazine or dicamba (in tank mixture or sequentially) produced similar corn yield to that applied alone. However, primisulfuron applied in tank mixture or sequentially with dicamba gave 22 and 14% lower yield, respectively, than when applied alone, and slightly lower when applied with atrazine.
Nomenclature: Atrazine, dicamba, primisulfuron, rimsulfuron, johnsongrass, Sorghum halepense (L.) Pers. #3 SORHA; corn, Zea mays L. ‘Pioneer Costanza’.
Additional index words: Sequential applications, tank mixtures.
Abbreviations: DAT, days after treatment.