ABSTRACT
Once-refined soybean, sunflower, and linseed oil, petroleum oil, and methylated soybean and sunflower oil with 17% v/v AT (Atplus 300F) emulsifier were evaluated as adjuvants with BAS-51702H (2-[l-(ethoxyimino) butyl]-3-hydroxy-5-(2H-tetrahydrofhiopyran-3-yl)-2-cyclohexen-l-one), sethoxydim, clopropoxydim, diclofop, quizalofop, fenoxaprop, and haloxyfop in the field. Methylated sunflower and soybean oils were more effective than petroleum oil or once-refined seed oils in enhancing grass control with BAS-51702H, sethoxydim, and clopropoxydim. Methylated soybean and sunflower oils were equal to petroleum oil and more effective than once-refined seed oils in enhancing grass control with diclofop, fenoxaprop, and haloxyfop. Grass control with quizalofop and fluazifop was enhanced equally with petroleum oil and methylated sunflower oil. Quizalofop was enhanced more by methylated sunflower oil than by methylated soybean oil.
Once-refined cottonseed, linseed, safflower, soybean, and sunflower oil, their methyl, ethyl, and butyl esters, and petroleum oil with 15% AT emulsifier were evaluated as adjuvants with cyanazine, AC-222,293 [methyl 6-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-m-toluate + methyl 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-p-toluate], diclofop, fluazifop, and sethoxydim in the greenhouse. Esterified seed oils were as good or better than petroleum oil or once-refined seed oils when applied with cyanazine, AC-222,293, diclofop, fluazifop, or sethoxydim. The crop origin of once-refined or esterfied seed oil generally did not influence the enhancement of herbicide phytotoxicity. The effect of oil adjuvant in the spray solution on the contact angle of the spray droplet was dependent upon the herbicide and the effect of these oil adjuvants on the contact angle did not appear to be related to their effectiveness in enhancing herbicide phytotoxicity.
The enhancement of fluazifop and sethoxydim phytotoxicity by nitrogen fertilizer-seed oil combinations were evaluated in the greenhouse. Ammonium sulfate or 28% UAN (urea: ammonium nitrate) enhanced phytotoxicity of fluazifop and sethoxydim when in combination with AT emulsifier or AT emulsifier plus oil. Generally, ammonium sulfate tended to enhance herbicide phytotoxicity more than 28% UAN when combined with the various oils or AT emulsifier.
