Table 10. Economic assessment for sulfur on Pacific Northwest wine 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
sulfur	powdery mildew	3137	610	4.0	5.1	$3.75	fenarimol myclobutanil triadimefon triflumizole mineral oil	0.05 0.10 0.15 0.25 20.00	$14.00 20.35 18.00 13.52 40.00	936	0	0	936	1,534
Oregon wine grapes
sulfur	powdery mildew	33434	5,106	4.0	6.5	$3.20	fenarimol myclobutanil triadimefon triflumizole mineral oil	0.05 0.10 0.15 0.25 20.00	$15.13 24.32 18.30 26.62 53.75	19,590	0	0	19,590	3,837
Washington wine grapes
sulfur	powdery mildew	30602	8,982	4.0	3.4	$3.50	fenarimol myclobutanil triadimefon triflumizole mineral oil	0.05 0.10 0.15 0.25 20.00	$11.68 20.80 18.30 18.00 40.00	17,000	0	0	17,000	1,893
Pacific Northwest Totals		67137	14,697		4.6		fenarimol myclobutanil triadimefon triflumizole mineral oil	0.05 0.10 0.15 0.25 20.00	$11.68 20.80 18.30 18.00 40.00	37530	0	0	37530	2554
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."

On Idaho wine grapes, sulfur was applied annually to an average 3,137 acres (610 base acres) between budbreak and veraison for control of powdery mildew. If sulfur were unavailable, sterol inhibitor applications would replace 90% of the acre treatments of sulfur, and mineral oil (JMS Stylet-Oil) applications would replace 10% of the acre treatments. The four sterol inhibitors, fenarimol, myclobutanil, triadimefon, and triflumizole, would replace sulfur in the same relative proportions that growers now use in Idaho. As more growers become familiar with JMS Stylet-Oil, its relative use will probably increase.

Sterol inhibitors and JMS Stylet-Oil would be applied about one-third less often than sulfur because they have a longer residual. On average, a 0.67 application of a sterol inhibitor or JMS Stylet-Oil would replace one application of sulfur. Yield quantity and quality would not change, unless resistance to the sterol inhibitors developed. The overall cost (replacement compounds) of replacing sulfur with sterol inhibitors and JMS Stylet-Oil would be $936,000 ($1,534 per base acre).

On Oregon wine grapes, sulfur was applied to 33,434 acres (5,106 base acres) between budbreak and veraison for control of powdery mildew. If sulfur were unavailable, mineral oil (JMS Stylet-Oil) applications would replace 70% of the acre treatments of sulfur and sterol inhibitor applications would replace 30% of the acre treatments. The four sterol inhibitors, fenarimol, myclobutanil, triadimefon, and triflumizole, would replace sulfur in the same relative proportions that growers now use in Oregon. Sterol inhibitors and JMS Stylet-Oil, because they have a longer residual, would be applied about one-third less often than sulfur.

On average, a 0.67 application of a sterol inhibitor or JMS Stylet-Oil would replace one application of sulfur.

Quantity and quality of yield would not change where JMS Stylet-Oil and sterol inhibitors replace sulfur, unless resistance to sterol inhibitors develops. The overall cost (replacement compounds) of replacing sulfur with mineral oil and sterol inhibitors would be $19.59 million ($3,837 per base acre).

On Washington wine grapes, sulfur was applied annually to an average 30,602 acres (8,982 base acres) between budbreak and veraison for control of powdery mildew. If sulfur were unavailable, sterol inhibitor applications would replace 80% of the acre treatments of sulfur, and JMS Stylet-Oil applications would replace 20% of the acre treatments. The four sterol inhibitors, fenarimol, myclobutanil, triadimefon, and triflumizole, would replace sulfur in the same proportions that growers now use in Washington. The relative use of JMS Stylet-Oil would probably increase as more growers become familiar with it.

Sterol inhibitors and JMS Stylet-Oil, because they have a longer residual, would be applied about one-third less often than sulfur. On average, a 0.67 application of a sterol inhibitor or JMS Stylet-Oil would replace one application of sulfur. Yield quantity and quality would not change, unless resistance to the sterol inhibitors developed. The overall cost (replacement compounds) of replacing sulfur with sterol inhibitors and JMS Stylet-Oil would be $17 million ($1,893 per base acre).

Sterol Inhibitors (fenarimol, myclobutanil, triadimefon and triflumizole)

The four sterol-inhibiting fungicides used on grapes are similar in mode of action, efficacy, and cost, so this assessment treats them as a group. Loss of any one of the four due to cancellation or resistance development would have a negligible impact, but loss of the whole group (i.e., from development of cross resistance) would greatly impair the ability of growers to control powdery mildew.

On all Pacific Northwest grapes, sterol inhibitors were applied to an average 59,743 acres (19,945 base acres) annually between budbreak and veraison for control of powdery mildew.

If sterol inhibitors were unavailable, sulfur and mineral oil would be applied. Both of these alternatives have disadvantages relative to sterol inhibitors. Sulfur, which must be applied at intervals as short as 7 days when mildew pressure is high, is not rainfast, can be phytotoxic under high temperature conditions, and can be irritating to the eyes and skin of farmworkers. The dust formulation of sulfur is the most effective at preventing mildew infection, but this formulation can be applied only under virtually windless conditions. Mineral oil also is not rainfast, and it can be phytotoxic if applied within 14 days of a sulfur application. The overall cost (replacement compounds, increased applications, and yield loss) of replacing sterol inhibitors with sulfur and mineral oil would be $7.61 million to $11.90 million ($411 to $645 per base acre). See also Table 11.

Table 11. Economic assessment for sterol-inhibiting fungicides on Pacific Northwest wine 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
fenarimol myclobutanil triadimefon triflumizole	powdery mildew	391	173	0.05 0.10 0.15 0.25	2.3	$14.00 20.35 18.00 13.52	sulfur mineral oil	4.0 20.00	$3.75 40.00	-100	15-25	154-256	54-99	310-573
Oregon wine grapes
fenarimol myclobutanil triadimefon triflumizole	powdery mildew	18,626	6,800	0.05 0.10 0.15 0.25	2.6	$15.23 24.32 18.30 26.62	sulfur mineral oil	4.0 20.0	$3.50 53.75	-1597	30-40	5,000, 6,668	3,403- 4,512	500-664
Washington wine grapes
fenarimol myclobutanil triadimefon triflumizole	powdery mildew	40,726	12,226	0.05 0.10 0.15 0.25	3.3	$11.68 20.80 18.30 18.00	sulfur mineral oil	4.0 20.0	$3.50 40.00	-1836	15-25	5,923- 9,872	4,087- 7,182	334-587
Pacific Northwest Totals		59,743	19,945		2.9					-3,464	15-40	11,077- 16,796	7,613- 11,897	411-645
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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