Materials and Methods
| Pesticide Usage Data |
| Expert Opinion and Biologic Assessment |
| Economic Assessment |
The initial step in the biologic and economic assessment of pesticides on Pacific Northwest grapes was collection of pesticide usage data. Different methods of data collection were used in each of the three states - Washington, Oregon, and Idaho.
Washington wineries and grape juice processors require growers to submit records of pesticide applications before they deliver their grapes. Records of 1992, 1993, and 1994 grower pesticide applications were obtained from several wineries and juice processors. Pesticide application records also were obtained from a private viticultural consultant who makes pest control recommendations to numerous Washington grape growers.
In total, pesticide application records were collected for 66% of the wine grape acres and 88% of the juice grape acres in Washington. The data from these records were assumed to be representative of the entire state; statewide base acres and acre treatments applied per year for each active ingredient were calculated from these data.
Data for Oregon wine grapes were obtained through Oregon State University. In 1995 OSU conducted a pesticide usage survey (see appendix) of Oregon grape growers. Survey forms were sent to all growers on the Oregon Winegrowers' Association mailing list. Follow up calls and visits were made to growers who did not return the survey form by mail. Data were obtained for 43% of the total wine grape acres in Oregon. The survey responses were assumed to be representative of the entire state; statewide base acres and acre treatments applied per year for each active ingredient were calculated from these data.
The Idaho wine industry is still relatively small. A list of growers was obtained from the Idaho Grape Growers and Wine Producers Commission, and all 26 growers on the list were contacted. These growers had a total of 610 acres of wine grapes, which comprise 100% of the wine grape acres in Idaho. The growers provided information on pesticides applied, rates of application, timing, and target pests.
Expert Opinion and Biologic Assessment
Because few data are available to predict the effects of the loss of a specific pesticide, expert opinion was used to conduct the biologic assessment. A list of expert cooperators is given in the Appendix.
Washington experts included an independent viticultural consultant, three viticulturists for a large winery, a general manager of another large winery, and two field representatives of large juice grape processors. Also included were a general manager of a large juice grape processor, a grower, a viticulture extension agent, a university entomologist, and two university weed scientists. Oregon experts included two growers, a viticulture extension specialist, a viticulture extension agent, a university entomologist, and a university plant pathologist. Idaho experts included a pest management coordinator for a large winery, the general manager of the Idaho Grape Growers and Wine Producers Commission, and three growers.
For each compound used on more than 10% of the wine or juice grape acres in each state, the experts were asked to name primary target pests, secondary target pests, percentage of acre treatments applied for each target pest, and the usual rate applied. They were also asked for their opinions on what would happen if the compound were no longer available, which compounds or nonchemical controls would be substituted, whether changes would be made in the number of applications or the rates of application, and what the impact would be on fruit yield, fruit quality, phytotoxicity risk, worker safety, and resistance management.
The experts' answers were pooled to form a single answer for each compound in each industry segment (Idaho wine grapes, Oregon wine grapes, Washington wine grapes and juice grapes). These composite answers comprise the biologic assessment.
The Pestcontrol Benefits Assessment (PBA3) model developed at Ohio State University was used to perform the economic assessment. Information on each industry segment (total acres, average production cost per acre, average yield, average harvest cost per ton, and average price per ton) was put into the model. Also added to the model was information on each pesticide (product price, application rate, application cost per acre, number of treatments per season, number of acres treated, and fruit yield and quality that would be achieved with the treatment) and nonchemical control (cost per acre, number of treatments per season, number of acres treated, and fruit yield and quality that would be achieved with the treatment). The model was then used to calculate the economic consequences of cancellation of each major pesticide in each industry segment. For each pesticide, changes were calculated in grower revenue due to yield and quality differences and changes in control costs resulting from the substitutions. These calculations resulted in a value for the total economic impact of cancellation of the compound for each industry segment.
Return to Table of Contents
Continue on to Biology and Control of Major Pacific Northwest Grape Pests