Oxyfluorfen

On all Pacific Northwest grapes, oxyfluorfen was applied to 5,268 acres (5,242 base acres) in the fall and spring for control of annual broadleaves and grasses (mainly broadleaves). This includes 2,111 acres (2,111 base acres) on juice grapes, 374 acres (374 base acres) on Idaho wine grapes, and 2,391 acres (2,366 base acres) on Washington wine grapes.

If oxyfluorfen were unavailable, oryzalin applications would replace 20% of the acre treatments of oxyfluorfen. Simazine, diuron, glyphosate, and mechanical cultivation would each replace 15% of the acre treatments of oxyfluorfen; norflurazon and paraquat would each replace 10% of the acre treatments of oxyfluorfen. Yield would remain unchanged on acres treated with oryzalin. A slight yield decrease (1%) would occur on acres treated with glyphosate, paraquat, and mechanical cultivation due to increased weed competition.

Simazine, diuron, and norflurazon tend to leach, so they might cause phytotoxicity in some vineyards, resulting in a 5% yield loss. This loss would decrease over time as growers learn on which soils they can and cannot apply the more leachable herbicides.

With three exceptions, all the alternative compounds would only need to be applied once to replace one application of oxyfluorfen. Exceptions include glyphosate, which would need to be applied twice per season; paraquat, which would need to be applied three times per season; and mechanical cultivation, which would be required six times per season. The overall cost (replacement compounds, increased applications, and yield loss) of replacing oxyfluorfen with oryzalin, simazine, diuron, glyphosate, mechanical cultivation, norflurazon, and paraquat would be $1.39 million ($286 per base acre) on all Pacific Northwest grapes. Cost would be $504,000 ($238 per base acre) on juice grapes, $33,000 ($88 per base acre) on Idaho wine grapes, and $871,000 ($368 per base acre) on Washington wine grapes. See also Table 17.

Table 17. Economic assessment for oxyfluorfen on Pacific Northwest wine and juice grapes.
Active ingredient	Target pest	Acres treated	Base acres	Rate lb ai/A	Treatments per year	Cost/A/ application	Alternatives	Rate lb ai/A	Cost/A/ application1	Æ2 Control costs (1000$)	ÆYield %	Æ Yield ($)	Total impact3 (1000$)	Impact/A4 ($)
Idaho wine grapes
oxyfluorfen	annual weeds	374	374	2.0	1	$92.50	diuron norflurazon glyphosate cultivation oryzalin simazine paraquat	2.40 2.36 1.00 6x 2.0 2.0 1.25	$12.75 54.05 13.75 8.50 37.50 9.34 18.00	17	0-5	16	33	88
Washington wine grapes
oxyfluorfen	annual weeds	2391	2366	2.0	1	$81.10	diuron norflurazon glyphosate cultivation oryzalin oxyfluorfen paraquat	2.40 2.36 1.00 6x 2.0 2.0 1.25	$19.20 55.49 12.91 8.50 40.37 9.34 19.47	670	0-5	201	871	368
Juice grapes
oxyfluorfen	annual weeds	2111	2111	2.0	1	$81.10	diuron norflurazon glyphosate cultivation oryzalin oxyfluorfen paraquat	2.40 2.36 1.00 6x 2.0 2.0 1.25	$19.20 55.49 12.91 8.50 40.37 81.10 19.47	412	0-5	92	504	238
Pacific Northwest totals		5268	5242	2.0	1					1,079	0-5	309	1,390	286
1Costs shown are for the pesticides only. Labor and equipment costs are about $6 per acre for each application. 2 Æ is a symbol that means "change in." 3Total impact is total cost to the growers, figured by adding Æ control costs and monetary Æ yield. A positive number is the cost to the grower. A negative number indicates a positive impact to growers. 4Total impact per base acre is the change in cost per acre to acres that have the pest problem and require use of the current pesticide."

Norflurazon

On all Pacific Northwest grapes, norflurazon was applied to 2,916 acres (2,916 base acres) in the fall and spring for control of annual grasses and broadleaves (mainly grasses). This includes 2,443 acres (2,443 base acres) for juice grapes and 82 acres (82 base acres) for Idaho wine grapes.

If norflurazon were unavailable, diuron applications would replace 30% of the acre treatments of norflurazon; simazine, glyphosate, and mechanical cultivation would each replace 15% of the acre treatments; oryzalin and oxyfluorfen would each replace 10% of the acre treatments; and paraquat would replace 5% of the acre treatments. Because diuron and simazine control a spectrum of weeds similar to those controlled by norflurazon, no yield loss would occur on acres where diuron and simazine replace norflurazon.

Oxyfluorfen and oryzalin control different spectrums of weeds; there would be a slight yield loss (1%) due to increased weed competition on acres where they are used. Glyphosate and paraquat, which are contact herbicides, are not good substitutes for norflurazon; increased weed competition would result in a 1% yield loss on acres where they are used.

Two applications of glyphosate would be needed to replace norflurazon, and three applications of paraquat would be needed. Use of mechanical cultivation also would result in a 1% yield loss due to increased weed competition, because cultivation is difficult between vines. Cultivation would be required six times per season to replace norflurazon. The overall cost (replacement compounds, increased applications, and yield loss) of replacing norflurazon with diuron, simazine, glyphosate, oryzalin, oxyfluorfen, paraquat, and mechanical cultivation would be $184,000 ($63 per base acre) for all Pacific Northwest grapes. Cost would be $97,000 ($40 per base acre) for juice grapes and $87,000 ($1,061 per base acre) for Idaho wine grapes. See also Table 18.

Table 18. Economic assessment for norflurazon on Pacific Northwest wine and juice grapes.
Active ingredient	Target pest	Acres treated	Base acres	Rate lb ai/A	Treatments per year	Cost/A/ application	Alternatives	Rate lb ai/A	Cost/A/ application1	Æ2 Control costs (1000$)	ÆYield %	Æ Yield ($)	Total impact3 (1000$)	Impact/A4 ($)
Idaho wine grapes
norflurazon	annual weeds	82	82	2.36	1	$54.05	diuron simazine glyphosate cultivation oryzalin oxyfluorfen paraquat	2.40 2.00 1.00 6x 2.0 2.0 1.25	$12.75 9.34 13.75 8.50 37.50 92.50 18.00	86	0-1	1	87	1061
Juice grapes
norflurazon	annual weeds	2443	2443	2.36	1	$55.19	diuron simazine glyphosate cultivation oryzalin oxyfluorfen paraquat	2.40 2.00 1.00 6x 2.0 2.0 1.25	$19.20 9.34 12.91 8.50 40.37 81.10 19.47	60	0-1	37	97	40
Pacific Northwest totals		2916	2916		1					146	0-1	38	184	63
1Costs shown are for the pesticides only. Labor and equipment costs are about $6 per acre for each application. 2 Æ is a symbol that means "change in." 3Total impact is total cost to the growers, figured by adding Æ control costs and monetary Æ yield. A positive number is the cost to the grower. A negative number indicates a positive impact to growers. 4Total impact per base acre is the change in cost per acre to acres that have the pest problem and require use of the current pesticide."

Diuron

On juice grapes, diuron was applied to 1,934 acres (1,934 base acres) in the fall and spring for control of annual broadleaves and grasses (mainly broadleaves). If diuron were unavailable, simazine applications would replace 30% of the acre treatments of diuron; norflurazon, glyphosate, and mechanical cultivation would each replace 15% of the acre treatments; oryzalin and oxyfluorfen would each replace 10% of the acre treatments; and paraquat would replace 5% of the acre treatments. Because simazine and norflurazon control a spectrum of weeds similar to those controlled by diuron, no yield loss would occur on acres where simazine and norflurazon replaced diuron.

Oxyfluorfen and oryzalin control different spectrums of weeds; there would be a slight yield loss (1%) due to increased weed competition on acres where they are used. Glyphosate and paraquat, which are contact herbicides, are not good substitutes for diuron; increased weed competition would result in a 1% yield loss on acres where growers substitute the two compounds for diuron. Two applications of glyphosate would be needed to replace diuron, and three applications of paraquat would be needed.

Use of mechanical cultivation would also result in a 1% yield loss due to increased weed competition, because cultivation is difficult between vines. Cultivation would be required six times per season to replace diuron. The overall cost (replacement compounds, increased applications, and yield loss) of replacing diuron with simazine, norflurazon, glyphosate, oryzalin, oxyfluorfen, paraquat, and mechanical cultivation would be $183,000 ($95 per base acre). See also Table 19.

Table 19. Economic assessment for diuron on Pacific Northwest juice grapes.

Active ingredient

Target pest

Acres treated

Base acres

Rate lb ai/A

Treatments per year

Cost/A/ application

Alternatives

Rate lb ai/A

Cost/A/ application1

Æ2 Control costs (1000$)

ÆYield %

Æ Yield ($)

Total impact3 (1000$)

Impact/A4 ($)

Juice grapes

diuron

annual weeds

1934

1934

2.4

1

$19.20

simazine norflurazon glyphosate cultivation oryzalin oxyfluorfen paraquat

2.00 2.36 1.00 6x 2.0 2.0 1.25

$9.34 55.49 12.91 8.50 40.37 81.10 19.47

146

0-1

37

183

95

1Costs shown are for the pesticides only. Labor and equipment costs are about $6 per acre for each application. 2 Æ is a symbol that means "change in." 3Total impact is total cost to the growers, figured by adding Æ control costs and monetary Æ yield. A positive number is the cost to the grower. A negative number indicates a positive impact to growers. 4Total impact per base acre is the change in cost per acre to acres that have the pest problem and require use of the current pesticide."

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