Herbicide Efficacy

June 14, 2016

Poplar stem and root control comparisons for 2,4-D, diphenoprop, dicamba and triclopyr

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
TREATMENT	Mix Rate/100L	Trembling aspen	Balsam poplar	Trembling Aspen	Balsam 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)

About the Author

Sig Guggenmoos | P. Ag. CPC President, Ecological Solutions Inc., Sherwood Park, Alberta, Canada

Education: Bachelor of Science in Agriculture B.Sc.(Agr.)

Accreditations: Professional Agrologist (P.Ag.); Certified Professional Consultant (CPC)

Organizations: Alberta Institute of Agrologists, International Society of Arboriculture, Utility Arborist Association, Industrial Vegetation Management Association of Alberta.

Mr. Guggenmoos was a chief architect of the TransAlta Utilities Distribution Line Clearance program, which reduced tree related outages 80%; saved 48 million dollars over two maintenance cycles; had a 98% customer satisfaction rating; and, showed a 21% increase in contractor crew productivity. He was responsible for the herbicide program, associated research and communication. In addition, he brought a financial focus to the program, developing processes for financial comparisons of alternatives to repetitive tree pruning and was intimately involved in the design and assessment of contracting methods.

As president of Ecological Solutions Inc. (Ecosync) Mr. Guggenmoos provides consulting services in vegetation management and biotic greenhouse gas mitigation strategies including biomass-derived energy.

Publications and Presentations:
Author of numerous abstracts and publications; numerous presentations to public, industry and professional associations including international conferences. List of publications available upon request.