WEED CONTROL IN ONION WITH POSTEMERGENCE HERBICIDES^††

Corey V. Ransom, Charles A. Rice, and Joey K. Ishida

Malheur Experiment Station

Oregon State University

Ontario, OR, 2004

Introduction

Weed control is essential for the production of marketable onions. Weed control in onions is difficult compared to many crops because of the lack of a complete crop canopy and limited herbicide options. Chateau^® (flumioxazin), formerly called Valor^®, and Nortron^® (ethofumesate) are two experimental herbicides that have been evaluated for use in onions in past research trials. Trials were conducted this year to determine the benefits of using these experimental herbicides in postemergence herbicide combinations and compare their performance to registered herbicide combinations.

Methods

General Procedures

Trials were conducted at the Malheur Experiment Station to evaluate experimental and registered herbicides for weed control and onion tolerance. Trials were conducted under furrow irrigation. On March 25, onions (cv. 'Vaquero', Nunhems, Parma, ID) were planted at 3.7-inch spacing in double rows on 22-inch beds. Plots were 4 rows wide and 27 ft long and arranged in a randomized complete block design with four replications. Lorsban^® was applied in a 6-inch band over each double row at 3.7 oz/1,000 ft of row. Onions were sidedressed with 175 lb nitrogen (N), 30 lb phosphorus (P), 35 lb sulfate, 38 lb sulfur (S), 2 lb Zinc (Zn), 3 lb manganese (Mn), and 1 lb boron (B)/acre on June 3. Registered insecticides and fungicides were applied for thrips and downy mildew control.

Herbicide treatments were applied with a CO₂-pressurized backpack sprayer. Preemergence applications and postemergence grass herbicides were applied at 20 gal/acre at 30 psi and postemergence treatments were applied at 40 gal/acre at 30 psi. All plots were treated with a preemergence application of Roundup^® (glyphosate) at 0.75 lb ai/acre plus Prow^®l (pendimethalin) at 1.0 lb ai/acre on April 5 and a postemergence application of Poast^® (sethoxydim) at 0.19 lb ai/acre plus crop oil concentrate (COC) (1.0% v/v) on June 16. Postemergence treatments were applied to two-leaf onions on May 6, two- to three-leaf onions on May 14, and to five-leaf onions on June 2. In the Chateau application timing trial, a separate application of Chateau was made to three-leaf onions on May 18. Weed control and onion injury were evaluated throughout the season. Onions were harvested September 16 and 17 and graded by size on October 1-4.

Data were analyzed using analysis of variance and means were separated using a protected least significant difference (LSD) at the 5 percent level (0.05).

Comparison of Postemergence Chateau or Goal Combinations

Chateau and Goal^® (oxyflurofen) were applied in combinations with Buctril^® (bromoxynil) to evaluate weed control and onion tolerance. Buctril, Goal, and Chateau were evaluated at two rates. Comparisons of Goal or Chateau with Buctril included several combinations of herbicides and rates. Additional treatments included a split application of Chateau applied to two-leaf and again to three-leaf onions, and a comparison of Buctril plus Chateau treatments following preemergence applications of Roundup, Prowl, and Dacthal^® (DCPA).

Application Timings for Chateau

Chateau was applied at two rates in combination with Buctril to two-leaf or three-leaf onions. Chateau treatments were compared to Goal plus Buctril. Additional treatments included Chateau in a separate application 4 days after the Buctril application at the three-leaf application timing.

Addition of Nortron to Postemergence Treatments

This trial was conducted to determine if the addition of Nortron to postemergence herbicide applications would improve weed control. Each treatment was applied with or without Nortron added to the two-leaf and three-leaf applications at either 0.25 or 0.5 lb ai/acre. One treatment evaluated Outlook^® (dimethenamid-P) added to the two-leaf application and Nortron added to the three-leaf application.

Results and Discussion

Preemergence herbicides worked fairly well due to rainfall in April. Adequate rainfall also ensured that weeds were actively growing when postemergence treatments were applied.

Comparison of Postemergence Chateau or Goal Combinations

Because the preemergence application of Prowl was so effective, there were no differences in weed control between any of the postemergence herbicide treatments (Table 1). Control of all species was 85 percent or greater. There were also no differences in onion injury among treatments. This is surprising as there were large differences in the herbicide rates applied for different treatments. There were a few differences in onion yields, with higher yields resulting from treatments with additional soil-active herbicides applied or with higher rates (Table 2).

Application Timings for Chateau

Treatment with Chateau combined with Buctril when applied either to two-leaf or three-leaf onions did not cause greater injury than combinations of Goal plus Buctril (Table 3). When Chateau was applied alone 4 days after Buctril was applied to three-leaf onions, injury increased significantly. By July 21 there were no differences in onion injury among treatments. The injury caused by the delayed application of Chateau was probably related to wet cool weather that occurred after the Buctril application and prior to the Chateau application. Pigweed (redroot pigweed and Powell amaranth), common lambsquarters, hairy nightshade, and barnyardgrass control was not different among herbicide treatments and was 88 percent control or greater. Kochia control was significantly greater with treatments that contained Chateau tank-mixed with Buctril and applied at either the two-leaf or three-leaf timing compared to Buctril plus Goal. Treatments where Chateau was applied alone following the Buctril application to three-leaf onions did not control weeds better than Buctril plus Goal.

There were few significant differences in onion yields between herbicide treatments, with marketable yields ranging from 1,107 to 1,459 cwt/acre.

Addition of Nortron to Postemergence Treatments

Onion injury was not different among treatments on either evaluation date (Table 5). Pigweed, hairy nightshade, and barnyardgrass control was similar among herbicide treatments and was 89 percent or higher. The addition of Nortron at either rate to Buctril significantly increased common lambsquarters control, but control was similar to that provided by Goal plus Buctril. There was no improvement in common lambsquarters control when Nortron was added to Buctril plus Goal. Kochia control was less when Buctril was applied alone compared to treatments containing Buctril plus Nortron or Goal or both. A few of the treatments containing Nortron produced more supercolossal onions than did Buctril alone, but yields were similar to the other herbicide treatments (Table 6). Nortron is useful for improving weed control in onion but in this trial did not provide greater benefits than the currently registered herbicides.

Table 1. Onion injury and weed control from Goal^® or Chateau^® combinations with Buctril^®, Malheur Experiment Station, Oregon State University, Ontario, OR, 2004.

			Injury			Weed control^†
Treatment	Rate	Timing*	5-24	6-9		Pigweed		Common lambsquarters	Hairy nightshade	Kochia	Barnyard-grass
	lb ai/acre	Leaf	----------------------------------------------------------------------------%-------------------------------------------------------------------------
Untreated	--	--	--		--		--	--	--	--	--
Roundup + Prowl Buctril Buctril + Goal Goal	0.75 + 1.0 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	24		28		86	90	96	95	100
Roundup + Prowl Buctril Buctril + Goal Goal	0.75 + 1.0 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	24		20		88	85	97	95	98
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.063 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	25		18		96	95	96	100	100
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.094 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	29		22		93	98	100	96	98
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.25 + 0.063 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	21		16		93	98	96	100	99
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.25 + 0.094 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	26		21		94	99	97	100	100
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	20		19		96	90	99	94	100
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.25 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	24		17		94	90	95	96	100
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.25 + 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	28		16		91	88	99	98	93

Table 1 (continued). Onion injury and weed control from Goal^® or Chateau^® combinations with Buctril^®, Malheur Experiment Station, Oregon State University, Ontario, OR, 2004.

			Injury			Weed control^†
Treatment	Rate	Timing*	5-24	6-9		Pigweed^‡		Common lambsquarters	Hairy nightshade	Kochia	Barnyard-grass
	lb ai/acre	Leaf	----------------------------------------------------------------------------%-------------------------------------------------------------------------
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.25 + 0.25 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	28		19		90	93	94	100	95
Roundup + Prowl Buctril + Chateau Buctril + Chateau Goal	0.75 + 1.0 0.125 + 0.047 0.25 + 0.047 0.25	PRE 2-leaf 3-leaf 5-leaf	25		18		95	97	97	88	100
Roundup + Dacthal + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 7.5 + 0.6 0.25 + 0.094 0.125 + 0.25 0.25	PRE 2-leaf 3-leaf 5-leaf	27		21		97	92	100	96	100
Roundup + Dacthal + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 7.5 + 0.6 0.125 + 0.094 0.125 + 0.25 0.25	PRE 2-leaf 3-leaf 5-leaf	27		18		96	98	100	100	100
Roundup + Dacthal + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 7.5 + 0.6 0.25 + 0.094 0.125 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	24		20		96	100	98	100	95
LSD (P = 0.05)	--	--	NS		NS		NS	NS	NS	NS	NS

*Preemergence (PRE) treatments were applied on April 5, two-leaf (2-leaf) on May 6, three-leaf (3-leaf) on May 14, and five-leaf (5-leaf) on June 2.

^†Weed-control ratings were taken September 2.

^‡Pigweed is a combination of redroot pigweed and Powell amaranth.

Table 2. Onion yield in response to Goal^® or Chateau^® combinations with Buctril^®, Malheur Experiment Station, Oregon State University, Ontario, OR, 2004.

			Onion yield^‡
Treatment	Rate	Timing*	Small	Medium	Jumbo	Colossal	S. Colossal	Marketable
	lb ai/acre	Leaf	----------------------------------------------------------- cwt/acre-------------------------------------------------------------------------
Untreated	--	--	0	0	0	0	0	0
Roundup + Prowl Buctril Buctril + Goal Goal	0.75 + 1.0 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	5	28	626	345	30	1,029
Roundup + Prowl Buctril Buctril + Goal Goal	0.75 + 1.0 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	4	13	527	540	150	1,229
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.063 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	7	16	481	522	141	1,160
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.094 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	6	17	559	510	123	1,208
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.25 + 0.063 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	4	18	580	453	115	1,167
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.25 + 0.094 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	5	17	562	490	207	1,275
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	7	48	595	348	111	1,101
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.25 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	3	13	497	524	181	1,216
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.25 + 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	8	20	583	361	78	1,041

Table 2 (continued). Onion yield in response to Goal^® or Chateau^® combinations with Buctril^®, Malheur Experiment Station, Oregon State University, Ontario, OR, 2004.

			Onion yield^‡
Treatment	Rate	Timing*	Small	Medium	Jumbo	Colossal	S. Colossal	Marketable
	lb ai/acre	Leaf	----------------------------------------------------------- cwt/acre-------------------------------------------------------------------------
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.25 + 0.25 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	5	16	502	592	167	1,277
Roundup + Prowl Buctril + Chateau Buctril + Chateau Goal	0.75 + 1.0 0.125 + 0.047 0.25 + 0.047 0.25	PRE 2-leaf 3-leaf 5-leaf	5	23	600	441	128	1,192
Roundup + Dacthal + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 7.5 + 0.6 0.25 + 0.094 0.125 + 0.25 0.25	PRE 2-leaf 3-leaf 5-leaf	3	18	461	552	207	1,238
Roundup + Dacthal + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 7.5 + 0.6 0.125 + 0.094 0.125 + 0.25 0.25	PRE 2-leaf 3-leaf 5-leaf	4	15	450	596	225	1,285
Roundup + Dacthal + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 7.5 + 0.6 0.25 + 0.094 0.125 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	4	18	484	552	168	1,222
LSD (P = 0.05)	--	--	5	18	185	180	122	193

*Preemergence (PRE) treatment applied on April 5, two-leaf (2-leaf) on May 6, three-leaf (3-leaf) on May 14, and five-leaf (5-leaf) on June 2.

^†Onions were harvested on September 16 and 17.

Table 3. Weed control and onion injury in response to Chateau^® application timings, Malheur Experiment Station, Oregon State University, Ontario, OR, 2004.

			Injury		Weed control^†
			Injury		Pigweed^‡	Common lambsquarters	Hairy nightshade	Kochia	Barnyard- grass
Treatment	Rate	Timing*	5-24	6-21	Pigweed^‡	Common lambsquarters	Hairy nightshade	Kochia	Barnyard- grass
	lb ai/acre	Leaf	---------------------------------------------------------------------------- % ------------------------------------------------------------------
Untreated	--	--	--	--	--	--	--	--	--
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	24	16	89	90	97	72	100
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.063 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	26	19	96	90	100	96	99
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.094 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	26	21	94	89	100	96	100
Roundup + Prowl Buctril + Goal Buctril + Chateau Goal	0.75 + 1.0 0.125 + 0.125 0.25 + 0.063 0.25	PRE 2-leaf 3-leaf 5-leaf	29	21	97	88	100	99	98
Roundup + Prowl Buctril + Goal Buctril + Chateau Goal	0.75 + 1.0 0.125 + 0.125 0.25 + 0.094 0.25	PRE 2-leaf 3-leaf 5-leaf	29	21	91	91	99	93	100
Roundup + Prowl Buctril + Goal Buctril Chateau Goal	0.75 + 1.0 0.125 + 0.125 0.25 0.063 0.25	PRE 2-leaf 3-leaf 3-leaf (S) 5-leaf	34	20	92	89	100	77	100
Roundup + Prowl Buctril + Goal Buctril Chateau Goal	0.75 + 1.0 0.125 + 0.125 0.25 0.094 0.25	PRE 2-leaf 3-leaf 3-leaf (S) 5-leaf	36	21	92	91	98	82	100
LSD (P = 0.05)	--	--	5	NS	NS	NS	NS	15	NS

*Preemergence (PRE) treatments were applied on April 5, two-leaf (2-leaf) on May 6, three-leaf (3-leaf) on May 14, three-leaf separate (3-leaf (S)) on May 18, and five-leaf (5-leaf) on June 2.

^†Weed control ratings were taken September 2.

^‡Pigweed is a combination of redroot pigweed and Powell amaranth.

Table 4. Onion yield in response to Chateau^® application timings, Malheur Experiment Station, Oregon State University, Ontario, OR, 2004.

			Onion yield^†
Treatment	Rate	Timing*	Small	Medium	Jumbo	Colossal	S. Colossal	Marketable
	lb ai/acre	Leaf	--------------------------------------------------------------------- cwt/acre ----------------------------------------------------------------
Untreated	--	--	0	0	0	0	0	0
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	4	18	639	385	75	1,117
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.063 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	4	16	519	535	110	1,179
Roundup + Prowl Buctril + Chateau Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.094 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	4	28	592	386	87	1,093
Roundup + Prowl Buctril + Goal Buctril + Chateau Goal	0.75 + 1.0 0.125 + 0.125 0.25 + 0.063 0.25	PRE 2-leaf 3-leaf 5-leaf	4	22	602	501	90	1,215
Roundup + Prowl Buctril + Goal Buctril + Chateau Goal	0.75 + 1.0 0.125 + 0.125 0.25 + 0.094 0.25	PRE 2-leaf 3-leaf 5-leaf	2	21	640	713	86	1,459
Roundup + Prowl Buctril + Goal Buctril Chateau Goal	0.75 + 1.0 0.125 + 0.125 0.25 0.063 0.25	PRE 2-leaf 3-leaf 3-leaf (S) 5-leaf	6	30	661	345	70	1,107
Roundup + Prowl Buctril + Goal Buctril Chateau Goal	0.75 + 1.0 0.125 + 0.125 0.25 0.094 0.25	PRE 2-leaf 3-leaf 3-leaf (S) 5-leaf	6	30	584	423	109	1,145
LSD (P = 0.05)	--	--	2	18	99	302	64	333

*Preemergence (PRE) treatments were applied on April 5, two-leaf (2-leaf) on May 6, three-leaf (3-leaf) on May 14, three-leaf separate (3-leaf (S)) on May 18, and five-leaf (5-leaf) on June 2.

^†Onions were harvested on September 16 and 17.

Table 5. Onion injury and weed control in response to the addition of Nortron^® to postemergence applications of Buctril^® and Goal^®, Malheur Experiment Station, Oregon State University, Ontario, OR, 2004.

Injury

Weed control^†

Pigweed^‡

Common

lambsquarters

Hairy nightshade

Kochia

Barnyard-

grass

Treatment

Rate

Timing*

5-24

6-9

lb ai/acre

Leaf

------------------------------------------------------------- %---------------------------------------------------------------

Untreated

Roundup + Prowl

Buctril

Buctril + Goal

Goal

0.75 + 1.0

0.125

0.25 + 0.125

0.25

PRE

2-leaf

3-leaf

5-leaf

100

Roundup + Prowl

Buctril + Goal

Goal

0.75 + 1.0

0.125 + 0.125

0.25 + 0.125

0.25

PRE

2-leaf

3-leaf

5-leaf

100

Roundup + Prowl

Buctril + Nortron

Buctril + Goal + Nortron

Goal

0.75 + 1.0

0.125 + 0.25

0.25 + 0.125 + 0.25

0.25

PRE

2-leaf

3-leaf

5-leaf

100

Roundup + Prowl

Buctril + Nortron

Buctril + Goal + Nortron

Goal

0.75 + 1.0

0.125 + 0.5

0.25 + 0.125 + 0.5

0.25

PRE

2-leaf

3-leaf

5-leaf

100

Roundup + Prowl

Buctril + Goal + Nortron

Goal

0.75 + 1.0

0.125 + 0.125 + 0.25

0.25 + 0.125 + 0.25

0.25

PRE

2-leaf

3-leaf

5-leaf

100

Roundup + Prowl

Buctril + Goal + Outlook

Buctril + Goal + Nortron

Goal

0.75 + 1.0

0.125 + 0.125 + 0.84

0.25 + 0.125 + 0.25

0.25

PRE

2-leaf

3-leaf

5-leaf

100

Roundup + Prowl

Buctril + Goal + Nortron

Buctril + Goal

0.75 + 1.0

0.125 + 0.125 + 0.5

0.25 + 0.125 + 0.5

0.125 + 0.25

PRE

2-leaf

3-leaf

5-leaf

100

LSD (P = 0.05)

*Preemergence (PRE) treatments were applied on April 5, two-leaf (2-leaf) on May 6, three-leaf (3-leaf) on May 14, and five-leaf (5-leaf) on June 2.

^†Weed control ratings were taken September 2.

^‡Pigweed is a combination of redroot pigweed and Powell amaranth.

Table 6. Onion yield in response to the addition of Nortron^® to postemergence applications of Buctril^® and Goal^®, Malheur Experiment Station, Oregon State University, Ontario, OR, 2004.

			Onion yield^†
Treatment	Rate	Timing*	Small	Medium	Jumbo	Colossal	S. Colossal	Marketable
	lb ai/acre	Leaf	------------------------------------------------------------- cwt/acre ---------------------------------------------------------------
Untreated	--	--	0	0	0	0	0	0
Roundup + Prowl Buctril Buctril + Goal Goal	0.75 + 1.0 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	8	45	689	225	12	971
Roundup + Prowl Buctril + Goal Buctril + Goal Goal	0.75 + 1.0 0.125 + 0.125 0.25 + 0.125 0.25	PRE 2-leaf 3-leaf 5-leaf	7	37	609	354	65	1,066
Roundup + Prowl Buctril + Nortron Buctril + Goal + Nortron Goal	0.75 + 1.0 0.125 + 0.25 0.25 + 0.125 + 0.25 0.25	PRE 2-leaf 3-leaf 5-leaf	6	29	693	349	60	1,130
Roundup + Prowl Buctril + Nortron Buctril + Goal + Nortron Goal	0.75 + 1.0 0.125 + 0.5 0.25 + 0.125 + 0.5 0.25	PRE 2-leaf 3-leaf 5-leaf	3	18	597	424	111	1,150
Roundup + Prowl Buctril + Goal + Nortron Buctril + Goal + Nortron Goal	0.75 + 1.0 0.125 + 0.125 + 0.25 0.25 + 0.125 + 0.25 0.25	PRE 2-leaf 3-leaf 5-leaf	4	33	640	363	72	1,107
Roundup + Prowl Buctril + Goal + Outlook Buctril + Goal + Nortron Goal	0.75 + 1.0 0.125 + 0.125 + 0.84 0.25 + 0.125 + 0.25 0.25	PRE 2-leaf 3-leaf 5-leaf	4	17	614	475	117	1,223
Roundup + Prowl Buctril + Goal + Nortron Buctril + Goal + Nortron Buctril + Goal	0.75 + 1.0 0.125 + 0.125 + 0.5 0.25 + 0.125 + 0.5 0.125 + 0.25	PRE 2-leaf 3-leaf 5-leaf	8	21	662	440	97	1,219
LSD (P = 0.05)	--	--	4	16	113	237	66	278

*Preemergence (PRE) treatment applied on April 5, two-leaf (2-leaf) on May 14, three-leaf (3-leaf) on May 18, and five-leaf (5-leaf) on June 2.

^†Onions were harvested on September 16 and 17.

^††The information in this report is for the purpose of informing cooperators in industry, colleagues at other universities, and others of the results of research in field crops. Reference to products and companies in this publication is for the specific information only and does not endorse or recommend that product or company to the exclusion of others that may be suitable. Nor should any information and interpretation thereof be considered as recommendations for the application of any pesticide. Pesticide labels should always be consulted before any pesticide use.