Issue link: https://read.dmtmag.com/i/350705
www.goodfruit.com GOOD FRUIT GROWER AUGUST 2014 51 About 50 flowering plant spe- cies were in the vicinity of the restored-habitat vineyards com- pared with approximately ten in the conventional vineyards. The restored-habitat vineyard sites were chosen because the growers had planted native species that were already established before James started the project. The restored and conventional vineyards were within a mile of each other. As an example of the pest management differences, in the Columbia Gorge trial, the restored-habitat vineyard had no insecticide applications last year compared with three in the nearby conventional vineyard. In another site, the Quincy restored-habitat vineyard came close to hav- ing a leafhopper issue, but the grower didn't spray, and Anagrus parasitoid wasps took care of the leafhoppers. Though James is still analyzing data from the proj- ect, he has put together an initial list of recommended fl owering plant species that attract benefi cial insects and mites (see "Top ten native plants"). Most of the ben- efi cial insects that were attracted are generalists that feed on "everything," he said, but as he further ana- lyzes data, he will be able to identify plants that attract specifi c benefi cials that are important. Expand research A key next step in the study is to expand the project to larger commercial vineyards and more locations within the state. Five plant species were planted as in-row ground cov- ers in WSU's research vineyard last year to learn more about the potential of using native plants as ground covers to bring beneficials inside the vineyard. The state's largest wine grape producer, Ste. Michelle Wine Estates, in collaboration with James, is also setting up research trials with native plants in four vineyard sites to monitor benefi cial impacts. Additionally, an educa- tional garden will be planted at WSU's new Wine Science Center to showcase native plant species and sustainable viticulture. James is presenting his data this summer to Walla Walla Valley wine grape growers during a workshop sponsored by Vinea, the Winegrow- ers Sustainable Trust. The $250,000 project was funded by Western Sus- tainable Agriculture Research and Education, North- west Center for Small Fruits, and the Wine Advisory Committee, the research arm of the Washington Wine Commission. He credits Walla Walla Valley wine grape growers with giving him the idea for the research and noted that several Walla Walla grape growers began doing this on their own ten years ago. "They had no idea what to plant or which ones would attract benefi cials, but they wanted to do something to bring diversity back to the vineyard." The concept is getting traction within the industry and gaining the interest of commercial growers, James said. "As growers experiment on their own, we'd like to be included in such trials so we can monitor the plots and add to our database. That's what we're lacking—data from whole blocks of commercial vineyards." Thus far, research has been in small plots. There's concern the plot size could be obscuring differences. "The plots are so small that by the end of the season, the benefi cial insects may be getting into our control plots. We need whole blocks so that we can compare to the neighbor down the road who's not using native plants and develop meaningful data." Washington grape growers are fortunate, he said, in having so few pest problems compared to other locations in the United States. "Growers couldn't do this very well in California because they have key pests," James said. "We have so few pests here, although we do have virus threat from grape mealybug. But we should promote our low pesticide-input viticulture status more than we do." In the works is a WSU manual on native plants and their attractiveness to benefi cial insects and their role in enhancing and sustaining integrated pest management in grapes. • Coyote mint growing in a native ground-cover trial in a WSU vineyard. Blooming rabbitbrush attracts dozens of benefi cial insect visitors. TOP TEN native plants A bout 60 plant species out of 120 studied by Washington State University's Dr. David James attract benefi cial insects and have potential native plants bout 60 plant species out of 120 studied by Washington State University's Dr. David James attract benefi cial insects and have potential native plants as ground cover or refugia plants for vineyards in eastern Washington. "Surprisingly, sagebrush is at the top of the list based on the mean number of benefi cials attracted," he said. But he calls sagebrush an unbalanced choice because it has a narrow attraction to mostly parasitic wasps. He's working to fi ne-tune the plant list to identify those that attract a diverse range of benefi cials instead of just a few types. His top ten list, based on preliminary data of all benefi cials attracted, include the following: 1. Big sagebrush (Artemesia tridentata)—attracts the greatest number of individual benefi cials, though mostly parasitic wasps and predatory (Artemesia tridentata)—attracts the greatest number of individual benefi cials, though mostly parasitic wasps and predatory (Artemesia tridentata) bugs. May be important overwintering resource. 2. Gray rabbitbrush (Ericameria nauseosa)—attracts large numbers and a wide range of benefi cials (bugs, thrips, parasitic wasps, and bees). (Ericameria nauseosa)—attracts large numbers and a wide range of benefi cials (bugs, thrips, parasitic wasps, and bees). (Ericameria nauseosa) Fall fl owering, overwintering resource plant. 3. Western clematis (Clematis ligusticifolia)—attracts large numbers and a wide range of benefi cials. Summer fl owering, refugia plant. (Clematis ligusticifolia)—attracts large numbers and a wide range of benefi cials. Summer fl owering, refugia plant. (Clematis ligusticifolia) 4. Native buckwheats (Eriogonum spp)—attracts large numbers and a wide range of benefi cials. Some are highly drought tolerant, mostly low growing. Ten species show potential. Summer and fall fl owering. 5. Yarrow (Achillea millifolium)—attracts large numbers and a wide range of benefi cials. Summer fl owering, ground cover. Readily available. (Achillea millifolium)—attracts large numbers and a wide range of benefi cials. Summer fl owering, ground cover. Readily available. (Achillea millifolium) Hardy plant. 6. Coyote mint (Monardella odoratissima)—attracts a range of benefi cials. Potential as ground cover if plant stays low enough. (Monardella odoratissima)—attracts a range of benefi cials. Potential as ground cover if plant stays low enough. (Monardella odoratissima) 7. Goldenrod (Solidago canadensis)—attracts a wide range of benefi cials. (Solidago canadensis)—attracts a wide range of benefi cials. (Solidago canadensis) 8. Showy milkweed (Asclepias speciosa)—attracts large numbers and a wide range of benefi cials. (Asclepias speciosa)—attracts large numbers and a wide range of benefi cials. (Asclepias speciosa) 9. Stinging nettles (Urtica dioica)—attracts large numbers of benefi cials and butterfl ies. Possibility as a ground cover, though may require (Urtica dioica)—attracts large numbers of benefi cials and butterfl ies. Possibility as a ground cover, though may require (Urtica dioica) more soil moisture than typical in eastern Washington vineyards. 10. Dog rose or Woods' rose (Rosa canina, Rosa woodsii)—Good overwintering plants but benefi cials also attracted to fl owers. (Rosa canina, Rosa woodsii)—Good overwintering plants but benefi cials also attracted to fl owers. (Rosa canina, Rosa woodsii) Native plants are usually sourced from nurseries as "plugs" and cost in the $2 to $3 range for a plug. Several nurseries specialize in native plant species, such as Derby Canyon Natives, owned by Ted Alway of Peshastin, Washington. If the right plants are chosen, they should require little water and take care of themselves once established. "The cost is in establishing the plant," he said, noting that if the right plant is chosen, there should be little upkeep. "It's a one-off, one- time cost." Growers may be able to receive some funds to help offset planting costs by tapping into local conservation district or U.S. Department of Agriculture programs that help fund wildlife/habitat restoration. —M. Hansen PHOTOS COURTESY OF DAVID JAMES, WASHINGTON STATE UNIVERISTY "We need to get the word out." —Dr. David James