Executive Summary

The Pacific Northwest grape industry has grown rapidly in the past decade. The Pacific Northwest has become one of the premier growing regions in the world for the wine grape, Vitis vinifera.

Washington surpassed New York in 1977 as the nation's largest producer of the juice grape, Vitis labrusca. The Pacific Northwest now encompasses about 42,572 grape acres. This acreage includes 12,862; 7,100; and 610 wine grape acres in Washington, Oregon, and Idaho, respectively, and 22,000 juice grape acres in Washington.

In 1994, Washington's wineries, then numbering 85, crushed 44,000 tons of grapes and sold more than six million gallons of wine. In the same year, Washington's five juice grape processors crushed 181,000 tons of Concord and Niagara juice grapes. Oregon wineries, numbering 101 in 1994, crushed 9,537 tons of grapes, more than one-third of which were Pinot Noir, and sold 1.5 million gallons of wine. Idaho, which has the youngest wine industry of the three states, had 12 wineries in 1994; crush and wine sales data were unavailable.

Pests

Insect pests can adversely affect the quantity and quality of wine and juice grapes produced in the Pacific Northwest. Two species of leafhopper, the western grape leafhopper, Erythroneura elegantula, and the Virginia creeper leafhopper, Erythroneura ziczac, feed on grape leaves by puncturing the leaf cells and sucking out the cell contents. Various species of thrips can damage wine grape shoots, leaves, and fruit. Two species of cutworm, the spotted cutworm, Amathes c-nigrum, and the redback cutworm, Euxoa ochrogaster, feed on developing grape buds in the early spring. Grape mealybug, Pseudococcus maritimus, produces a honeydew that makes the fruit, shoots, and foliage sticky. Cottony maple scale crawlers, Pulvinaria vitis, also excrete honeydew onto the vines. A black fungus, Cladosporium spp., grows on the honeydew deposited by mealybug and scale, producing a sooty mold. Black vine weevil, Otiorhynchus sulcatus, feeds on grape clusters and leaves, girdling the cluster stems and berry stems.

Two diseases, powdery mildew and bunch rot, can seriously threaten wine grape quality. Powdery mildew, caused by the fungus Uncinula necator, is the most important pest of Pacific Northwest wine grapes. Juice grapes normally are considered resistant to mildew, but some juice grape vineyards had powdery mildew in 1995. When more than 5% of wine grape berries are mildew-infected, the wine made from the fruit can have a distinct off-flavor. Most wineries will reject mildew-infected fruit.

Bunch rot is caused mainly by Botrytis cinerea. Botrytis-infected clusters are vulnerable to infection by secondary rot fungi, including Aspergillus niger and Penicillium expansum. Bacteria, Acetobacter spp., and yeasts, Candida spp., can also invade the infected clusters, causing a vinegar-smelling "sour rot." Wineries may also reject bunch rot-infected fruit.

Annual weeds and perennial weeds compete with grapevines for soil nutrients and water. In newly planted vineyards, uncontrolled weeds easily can outgrow vines and deprive them of light. Even in established vineyards, thick stands of weeds can reduce vine vigor and yield. Weeds such as marestail, Conyza canadensis, which grow up into the vine canopy, can interfere with harvest and other field operations. Weeds also serve as hosts for leafhopper, cutworm, and possibly other grape pests.

Marestail; puncturevine, Tribulus terrestris; green foxtail, Setaria viridis; sandbur, Cenchrus longispinus; bursage, Ambrosia acanthicarpa; kochia, Kochia scoparia; and Russian thistle ,Salsola iberica, are some of the most difficult annual weeds to control in Pacific Northwest vineyards. Problem perennial weeds include field bindweed, Convolvulus arvensis; Canada thistle, Cirsium arvense; bermudagrass, Cynodon dactylon; and quackgrass, Agropyron repens.

Assessment Methods

Pesticide usage data were collected from each of the four industry segments: Washington wine grapes, Oregon wine grapes, Idaho wine grapes, and Washington juice grapes. Expert opinion was then used to determine the biologic value of each active ingredient used on more than 10% of the acres in one or more industry segments. The experts were asked a series of questions on the consequences of loss of availability for each active ingredient. We assume single loss of active ingredient in our calculations. The experts' answers were pooled to form a single answer for each active ingredient in each industry segment.

The Pestcontrol Benefits Assessment (PBA3) model by Lemon, J. and Robin Taylor, PBA, Pestcontrol Benefits Assessment Rev. 3.01, Guide & Tutorial. Ohio State University, 1995 was used to perform the economic assessment. Data on each industry segment were put into the model, along with information on each active ingredient and nonchemical control. The model then was used to calculate the economic consequences of cancellation of each major pesticide in each industry segment. Table 1 shows total impact and per acre impact of pesticide use on grapes. Table 2 shows the state-by-state breakdown of base and treated acres for active ingredients used on Pacific Northwest grapes. In this report, base acres are those acres upon which a crop is grown. Treated acres are base acres multiplied by the number of treatments applied to the base acres.

Table 1. Per treated acre and total impacts of pesticide use on grapes*.
	WA			OR			ID			Juice grapes			Total
Active ingredient	Impact/Acre	Total		Impact/Acre	Total		Impact/Acre	Total		Impact/Acre	Total		Impact/Acre	Total
Insecticides
Dimethoate	33	160000					41	4000					26	164000
Carbaryl	39	65000					2	1000					27	66000
Chlorpyrifos	1179	$1.55M								1277	$1.37M		1223	$2.92M
Endosulfan	30	52000
Mineral Oil							77	24000
Carbofuran										$1,105 - $2,210	$1M-$2M
Fungicides
Sulfur	1893	$17M		3837	$19.59M		1534	936000					2554	$37.53M
Sterol-inhibitors	$334-$587	$4.09M-$7.18M		$500-$664	$3.40M-$4.51M		$310-$573	54000-99000					$411-$645	$7.61M-$11.90M
Iprodione				1534	$5.50M
Herbicides
Glyphosate	78	540000					65	34000		89	976000		80	$1.89M
Paraquat	112	360000		87	126000		57	5000		86	238000		96	729000
Simazine	136	295000		73	137000					76	260000		92	692000
Oxyfluorfen	368	871000					88	33000		238	504000		286	$1.39M
Oryzalin	672	$1.45M											96	578000
Norflurazon							1061	87000		40	97000		63	184000
Diuron										95	183000		95	183000
*Impact/Acre is the total impact per base acre. It represents the change in cost per acre to those acres having the pest problem requiring use of the current pesticide.

Table 2. State by state breakdown of base and treated acres for active ingredients used on Pacific Northwest grapes.
		WA			OR			ID			Juice			Total
Active ingredient		Base acres	Treated acres		Base acres	Treated acres		Base acres	Treated acres		Base acres	Treated acres		Base	Treated
Insecticides
Dimethoate		4833	5035		1057	1057		97	97		329	329		6316	6518
Carbaryl		1660	1701		247	275		430	479		113	113		2450	2568
Endosulfan		1740	1851											1740	1851
Petroleum oil		413	413		38	38		311	311		875	878		1637	1640
Diazinon		258	303		1057	1057					42	42		1357	1402
Malathion-methoxychlor		131	131								54	54		185	185
Malathion		165	165								31	31		196	196
Azinphos-methyl		300	300								248	248		548	548
Chlorpyrifos		1314	1349								1073	1075		2387	2424
M-Pede		290	300		275	281								565	581
Propargite		59	59											59	59
Methomyl		14	14					26	26		69	69		109	109
BT		21	21											21	21
Vegetable oil		37	37											37	37
Pyrethrins		28	28											28	28
Carbofuran											181	181		181	181
Herbicides
Glyphosate		6949	9779		4968	6645		526	581		10991	12669		23434	29674
Paraquat		3207	3284		1445	1810		90	245		2761	3017		7503	8356
Oxyfluorfen		2368	2391		391	391		374	374		2111	2111		5244	5267
Oryzalin		2157	2172		527	527		24	24		6023	6023		8731	8746
Simazine		2163	2208		1884	1884		29	29		3443	3454		7519	7575
Norflurazon		368	368		24	24		82	82		2443	2443		2917	2917
Napropamide		64	64		209	209					1446	1446		1719	1719
Pronamide		38	38											38	38
Diuron		20	20		156	156		14	14		1934	1934		2124	2124
2,4-D		53	53		654	701					675	681		1382	1435
Trifluralin		12	12					14	14		241	241		267	267
Pendimethalin		10	10					8	8					18	18
Sethoxydim											9	9		9	9
Fungicides
Fenarimol		9358	33488		2327	8466		153	348					11838	42302
Sulfur		8982	30602		5106	33434		610	3137					14698	67173
Myclobutanil		2035	6134		4377	8465		4	4					6416	14603
Triadimefon		833	1104		539	1126		16	39					1388	2269
Iprodione		393	641		3586	6986								3979	7627
Copper					2095	3542								2095	3542
Lime sulfur					908	1679								908	1679
Benomyl					415	589								415	589
Soap					396	503								396	503
Triflumizole					302	569		8	8					310	577
Stylet oil					221	439								221	439
Mancozeb					174	204								174	204
Captan					139	169								139	169
DCNA					99	99								99	99

Assessment Results

Conclusions
Cancellation of chlorpyrifos, carbofuran, sulfur, the sterol-inhibiting fungicides, iprodione, or glyphosate would be especially costly to the Pacific Northwest grape industry. Chlorpyrifos, which is available due to an emergency exemption (Section 18), is the only effective compound available for cutworm control. Carbofuran is the only active ingredient registered for black vine weevil control. Loss of chlorpyrifos or carbofuran could lead to extensive insect damage in both wine and juice grape vineyards. Cancellation of sulfur or the sterol-inhibiting fungicides would greatly impair growers' ability to control powdery mildew. Loss of sulfur likely would lead to fungus developing resistance to sterol inhibitors, leaving growers with no alternatives. Loss of sterol inhibitors would force growers to rely mainly on sulfur, which requires almost windless weather conditions for application and must be applied more often than sterol inhibitors. Cancellation of iprodione would leave growers in bunch-rot-prone areas with no effective product to control the disease. Glyphosate also has no useful alternatives; it is the only postemergence systemic herbicide available for use in vineyards. Loss of glyphosate would make control of perennial weeds especially difficult.

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