Poplar stem and root control comparisons for 2,4-D, diphenoprop, dicamba
and triclopyr. Guggenmoos, S.
A survey of stem and root kill provided by commercial applications
of four herbicides, 2,4-D, 2,4-D:2,4-DP, 2,4-D + dicamba and triclopyr applied
on powerline right of ways through the 1989 growing season was undertaken.
Eleven townships ranging from 35-27W4 north to 63-26W4 were sampled. Random
samples of 10 trembling aspen and/or ten balsam poplar were taken per site.
Wherever possible a total of 30 sprayed individuals per species per treatment
constituted the total sample for a township. Since townships had been randomly
chosen without prior knowledge of brush density, a full complement of 30
individual samples consisting of 3 replicates could not be achieved at all
times. All the data was included for analysis. Sample size ranged from a low of
40 for diphenoprop to a high of 140 for triclopyr on trembling aspen. Data
collection occurred from August through October 1991. Mix rates are indicated
in the table below. All target brush was sprayed to the point of run-off with
volumes ranging from 1,1OOL/ha to about 2,800L/ha. Two methods of application
were employed, hose and gun and boom mounted nozzles. No attempt was made to
separate the samples on the basis of application method or timing.
Efficacy comparisons of common brush control
herbicides
STEM
KILL (%) SPROUT
FACTOR2
Mix Rate Trembling
Balsam Trembling
Balsam
TREATMENT
/lOOL aspen
poplar aspen poplar
2;4-D1
480g 86
b3
71 b 3
a
23 b
2,4-D:2,4-DP
(1:1)
700g 98
c
99 c 35
b
0 a
2,4-D +
dicamba
400g + 200g 82
b
74 b 9
a
6 a
triclopyr
ester
288g 90
b
91 c 6
a
10 ab
Control 1
a
1 a 0
a
0 a
1all herbicide treatments include
NalcoTrol at 0.03% V/V
2number of sprouts X maximum sprout
length
3Duncan's Multiple range Test at 5%
level
Diphenoprop provided excellent stem kill of both trembling aspen and balsam
poplar. Considerable and significant suckering of trembling aspen occurred
while suckering on balsam poplar was virtually non-existent in spite of
excellent top growth control. Triclopyr provided very good stem kill of both
poplar species. Root suckers were found for both poplar species but were not
significantly greater than the control. Fair to good stem kill was provided by
both 2,4-D and dicamba plus 2,4-D. Root suckering was not significant for the
dicamba mixture but the 2,4-D alone resulted in significant root suckering of
balsam poplar. (TransAlta Utilities, Sherwood Park, Alberta)