Title

Buckwheat response to preemergence herbicides

(Research Report, Hettinger REC, November 2023)

File

Publication File:

Summary

A trial was conducted to evaluate the tolerance of buckwheat to preemergence herbicides. Buckwheat “Koto” was seeded on May 31, 2023 near Hettinger, ND using a no-till drill with a row spacing of 7.5 inches at seeding rate of 50 lbs/A at a depth of 1.25 inches. Herbicide treatments (Table 1) were applied on the same day after seeding using a tractor-mounted research sprayer. Herbicides evaluated were applied at a 1X and 2X rate of typical used rates for other crops grown in southwest North Dakota. Buckwheat emerged on June 7. Injury to buckwheat was evaluated on June 20 (2 weeks after treatment (WAT)). Stand counts of buckwheat were measured on June 19. Injury to buckwheat was greatest (43%) with the 2X rate (8 oz ai/A) of metribuzin, which also reduced stand count by 41%. However, even with the reduction in stand count, buckwheat yield was similar to the untreated control. Moderate injury was also observed in buckwheat treated with the 1X rate of metribuzin, the 2X rate of dimethenamid, and the 2X rate of mesotrione. Stand count was reduced for the 1X rate of metribuzin, but were not significantly reduced from the other two treatments, but buckwheat height was reduced for both of these treatments. Again, these treatments did not significantly reduce yield compared with the untreated control. Slight injury was observed following application of metolachlor, pyroxasulfone, and 1X rates of dimethenamid, and mesotrione. No injury was observed following application of isoxaflutole or topramezone. Yield was greatest following the 2X rate of isoxaflutole, likely due to reduction in weed competition. Further evaluations of herbicides for buckwheat is needed as none of the herbicides tested are currently labelled for use.

Lead Author

Lead Author:

Caleb Dalley

Availability

Availability:

Web only

Publication Sections

Table 1. Buckwheat response to preemergence herbicides at Hettinger, ND.

Herbicide Treatment^a		Rate	Injury^b		Stand count		Height		Yield
		oz ai/A	%		plantsA		Inch		LB/A
1	Untreated		0	g	517000	ab	22	a	1162	bc
2	Metribuzin	4	17.5	cd	359000	cd	21	abc	1431	ab
3	Metribuzin	8	42.5	a	303000	d	13	f	1017	c
4	s-Metolachlor	25	4.5	ef	528000	ab	22	a	1097	bc
5	s-Metolachlor	50	16.8	cd	512000	ab	18	de	1237	abc
6	Dimethenamid-p	12	8.3	de	470000	ab	19	cd	1076	c
7	Dimethenamid-p	24	30	ab	470000	ab	16	ef	1180	bc
8	Pyroxasulfone	1.3	2.5	fg	530000	ab	21	ab	1329	abc
9	Pyroxasulfone	2.6	10.8	d	442000	bc	16	ef	1343	abc
10	Mesotrione	1.25	2.5	fg	463000	abc	20	bcd	1162	bc
11	Mesotrione	2.5	25	bc	438000	bc	20	bcd	1196	bc
12	Isoxaflutole	0.75	0	g	507000	ab	21	ab	1158	bc
13	Isoxaflutole	1.5	0	g	494000	ab	21	ab	1539	a
14	Topramezone	0.35	0	g	566000	a	23	a	1045	c
15	Topramezone	0.7	0	g	533000	ab	22	a	1095	c
LSD P=.05			8.57		103000		2.3		310.02
Standard Deviation			6.01		72338.8		1.6		216.18
CV			56.25		14.54		7.56		18.83
Treatment Prob(F)			0.0001		0.0004		0.0001		0.0205

Table 2. Description of herbicide application and equipment for treatments applied in buckwheat to evaluate tolerance to preemergence herbicides at Hettinger, ND, 2023.

Application Description		Application Equipment
Date	5/31/2023	Equipment Type	Tractor
Start Time	8:38 AM	Operation Pressure	37 PSI
Stop Time	9:25 AM	Nozzle Model	11003
Air Temperature	80 F	Nozzle Type	DRIRED
Relative Humidity (%)	51	Nozzle Spacing	20 IN
Wind Velocity+Dir. Start	2.6 MPH, ENE	% Coverage	100
Wind Velocity+Dir. Stop	0 MPH, ESE	Boom Length	100 IN
Wind Velocity+Dir. Max	4.9 MPH, E	Boom Height	22.0 IN
Soil Temperature	65 F	Ground Speed	4.5 MPH
% Cloud Cover	100	Application Amount	10 GAL/AC
		Mix Size	2 L
		Propellant	CO2

Buckwheat response to preemergence herbicides

Table 1. Buckwheat response to preemergence herbicides at Hettinger, ND.

Table 2. Description of herbicide application and equipment for treatments applied in buckwheat to evaluate tolerance to preemergence herbicides at Hettinger, ND, 2023.

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