Ceronio, G. M.De Villiers, B. L.Chiconela, Tomás Fernando2017-04-252017-04-251998http://hdl.handle.net/11660/6147The effects of spray carrier, pH, adjuvants and ammonium salts, environmental factors, and spray volume on sethoxydim {2-[ 1-ethoxyirnino-butyl]-5-[2-( etylthio )propyl]-3- hydroxy-2-cyclohexen-1-one} activity in a glasshouse on tomato (Lycopersicum esculentum L cv. Star 9001) and oats (Avena sativa L cv. SSH 241) were studied. Sodium bicarbonate, potassium carbonate and spray solution pH were antagonistic to sethoxydim phytotoxicity. Spray solution pH and ions present were antagonistic to sethoxydim phytotoxicity only when the spray carrier pH exceeded 6.5. Sadol and ammonium salts (ammonium nitrate and ammoruum sulfate) were equally effective in enhancing sethoxydim activity regardless of the presence of antagonistic salts. Bladbuff 5 was moderately effective in the enhancement of sethoxydim phytotoxicity only when sethoxydim was applied at 186.0 g ai.ha¹ and not at 139.5. Addition of Agral 90 and Break- Thru were not beneficial, or were both of little value as adjuvants with sethoxydim. Sethoxydim applications at temperatures ranging between 25 and 35°C were equally more effective as compared to 15°C. However, Sadol, Break- Thru and ammonium salts were most effective in enhancing sethoxydim performance at 25°C than at 15 or 35°C. When averaged across sethoxydim rates and the presence of sodium bicarbonate and in potassium carbonate in the spray solution, oat fresh top mass reduction increased as carrier volume was decreased from 875 to 175 l.ha¹. In all the experiments conducted, tomato plants did not show any injury to negative growth suggesting that sethoxydim may be considered for control of grass weeds in tomatoes.enHerbicides -- Environmental aspectsTomatoes -- Weed controlDissertation (M.Sc.Agric.(Agronomy))--University of the Free State, 1998DissertationUniversity of the Free State