Tralkoxydim: adjuvant, MCPA and other effects

The effects of sodium bicarbonate, ammonium salts, mineral oil adjuvants, MCPA and time of day applied were determined for tralkoxydim activity. The influence of MCPA and sodium bicarbonate on herbicide rainfastness was also investigated. All the ammonium salts used overcame sodium bicarbonate antagonism. Ammonium salts were also beneficial in deionized water. Ammonium sulphate was the most effective salt followed by ammonium nitrate. Ammonium bicarbonate and ammonium hydroxide were less effective in sodium bicarbonate containing carriers. TF 8035 was a more effective mineral oil adjuvant than Addit. Ammonium sulphate further increased herbicide activity especially with Addit. Ammonium sulphate was effective with TF 8035 only in the sodium bicarbonate containing carrier water. MCPA was antagonistic to tralkoxydim and ammonium sulphate could not overcome the antagonism but enhanced the activity of the tralkoxydim – MCPA combination. Herbicide efficacy increased when applied in the evening and this was most pronounced in sodium bicarbonate carriers. Rain 30 min after application reduced its activity, but had no effect when tralkoxydim was applied with MCPA. In certain cases, rain improved herbicide activity with MCPA. The results indicate the importance of antagonistic carriers and combinations, adjuvants, ammonium salts and time of day applied on tralkoxydim activity and rainfastness.