Absorption and translocation of14C following14C-fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} butyl ester and14C-sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} application to oats (Avena sativaL. ‘Lyon’) was greater when the herbicides were applied with oleic acid, linoleic acid, or fatty acid methyl esters compared to various triglycerides. The methyl esters of stearic, oleic, linoleic, and linolenic acids enhanced14C absorption and translocation when applied with14C-fluazifop and14C-sethoxydim, except that the methyl ester of stearic acid did not enhance14C absorption and translocation when applied with14C-sethoxydim. The absorption and translocation of14C following the application of14C-CGA-82725 {(±)-2-[4-(3,5-dichloro-2-pyridyloxy)phenoxy] propanoic acid)-2-propynylester},14C-diclofop {(±)-2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid},14C-fluazifop, and14C-sethoxydim were generally enhanced equally or greater by the methyl ester of sunflower (Helianthus annumL.) oil than by petroleum oil additive or once refined sunflower oil. Methylated sunflower oil was equally or more effective as an additive than petroleum oil in enhancing grass control with fluazifop and sethoxydim in a field experiment.

Quackgrass biotypes collected from 15 locations exhibited differential response to primisulfuron at 20 g ha−1in field experiments at Hudson, NY during 1990 and 1991. Quackgrass control ranged from 23 to 100% 77 days after application (DAA) in 1990 and from 38 to 100% 88 DAA in 1991. The biotype from Montpelier, OH was the most tolerant both years. Differential response of quackgrass biotypes from five locations was confirmed in greenhouse experiments. The primisulfuron rate required to reduce shoot regrowth by 50% in the greenhouse was estimated at 15, 15, 17, 17, and 37 g ha−1for biotypes from Amherst, MA; Mahnomen MN; Fargo, ND; State College, PA; and Montpelier, OH, respectively. Quackgrass shoot regrowth was reduced more when primisulfuron was applied with the linear alcohol ethoxylate additive 1412-70 compared with Scoil, Sylgard 309, Agridex, or X-77.

GILr-Esere , G. R. eNo Mrr-r-En, S. D.Can. J. Plant Sci. 64: 105-111. 1984. Sunflower

Field experiments were conducted during 1984 and 1985 to determine the influence of 2,4-D and MCPA amine and ester formulations on control of foxtail millet with diclofop. Foxtail millet control increased as the diclofop rate increased from 0.6 to 1.7 kg ai/ha whether diclofop was applied alone or with 2,4-D or MCPA amine and ester formulations; however, foxtail millet control was lower when diclofop was applied with 2,4-D or MCPA amine and ester formulations compared to diclofop applied alone. MCPA ester, MCPA amine, 2,4-D ester, or 2,4-D amine at 0.14 kg ai/ha added to a diclofop spray mixture reduced foxtail millet control 8, 15, 20, and 30% compared to diclofop applied alone, averaged over diclofop rates of 0.6, 0.8, 1.1, 1.4, and 1.7 kg/ha. Adding a petroleum oil to diclofop increased foxtail millet control with diclofop at 0.6 kg/ha but not at 0.8 kg/ha. The petroleum oil additive did not overcome the antagonism of foxtail millet control when diclofop at 0.6 kg/ha was applied with 2,4-D or MCPA amine and ester formulations. The amount of14C-diclofop absorbed by oats was greater when diclofop was applied with the ester formulations of 2,4-D or MCPA compared to the amine formulations. Either once-refined sunflower oil or sunflower oil methyl ester applied with14C-diclofop increased the amount of14C absorbed and translocated in oat plants compared to14C-diclofop applied alone.

Factors accounting for the differential response of five quackgrass biotypes to primisulfuron were compared. Previous field and greenhouse experiments had identified a biotype from Montpelier, OH, as being less susceptible to primisulfuron than biotypes from Amherst, MA; Mahnomen, MN; Fargo, ND; and State College, PA. Differences in shoot, root, and rhizome fresh weights and rhizome bud numbers did not account for the reduced susceptibility of the Montpelier, OH, biotype to primisulfuron. Spray retention was lower in biotypes from OH and MA compared to the others. Absorption of14C following14C-primisulfuron application was greater in the Amherst, MA, biotype compared to the others. Only 29% of absorbed14C was present as primisulfuron in the Montpelier, OH, biotype versus 41 to 45% in the other biotypes 72 h after application. The amount of primisulfuron present in the Montpelier, OH, biotype 72 h after application was less than half the amount present in the other four biotypes due to reduced spray retention and faster metabolism. These factors combined explain lower susceptibility of the Montpelier, OH, biotype to primisulfuron.