Enhancement of phenoxy effects by addition of Assist. Guggenmoos, S. 

Stem kill was previously reported in this trial where Assist oil concentrate was added to a commercial application of diphenoprop intended to control 2 metre regrowth of tall growing tree species on a power line right of way in the Judy Creek oilfield, Alberta. Application occurred between August 12 and 14, 1987 using a hose and gun from both aerial bucket and soft track machines. Assist, at 0.5% v/v, was added to a mix of 350 g 2,4-D plus 350 g 2,4-DP per 1000 L solution. Brush was sprayed to the point of run-off with an average volume of 1885 L/ha. Stem kill, sprouts and sprout length were evaluated for poplar species on October 25, 1989. These results are compared with the standard treatment of 350 g 2,4-D plus 350 g 2,4-DP per 1000 L solution sprayed to run-off. Data for the standard is derived from previous trials.

Comparison of diphenoprop vs diphenoprop + Assist for brush control

TREATMENT a.i./1000 L Trembling aspen Balsam poplar Trembling aspen Balsam poplar
2,4-D + 2,4-DP 350g + 350g 9 b1 4 a 118 b1 20 a
2,4-D + 2,4-DP + Assist 350g + 350g + 0 .5% 9 b 9 b 107 b 18 a

1Duncan’s Multiple Range Test at 5% level

2number of sprouts X maximum sprout length

Stem kill for balsam poplar was significantly increased by the addition of Assist at 0.5%

v/v. No significant reduction in sprout formation and growth, as indicated by the sprout factor,

was observed. (TransAlta Utilities, Sherwood Park, Alberta)