Issue link: http://read.dmtmag.com/i/298602
www.goodfruit.com GOOD FRUIT GROWER MAY 1, 2014 41 U sing nematode-resistant rootstocks is one of the most effective ways to manage the parasite in grape vineyards, says a former U.S. Department of Agriculture grape breeder. Several new nematode-resistant rootstocks have recently been released and more are coming. Root knot nematodes are among the most damaging pests of grapevines in the United States, said Dr. Peter Cousins, former grape breeder and geneticist for USDA in Geneva, New York, who now is in charge of grape plant improvement at E & J Gallo in Modesto, California. Nema- todes are microscopic worms that feed on roots and cause damage by reducing vine yields and limiting the vine's water and nutrient uptake. Root knot nema- todes cause more than $1 billion in damage annually to U.S. viticulture. Vitis vinifera cultivars are particularly sensitive. In the past, rootstocks have not been used much in eastern Washington vineyards because of the periodic need to retrain vines up from the ground after winter damage. But a growing nematode problem and other replant issues are forcing Washington growers to con- sider nematode-resistant rootstocks as an alternative to soil fumigants and other chemical nematicides. Thanks to a refocus of several grape-breeding pro- grams, improved nematode-resistant grape plant mate- rial is now available, giving growers several choices, said Cousins, who spoke at the annual meeting of the Washington Association of Wine Grape Growers. There are six grape-breeding programs in the world working on nematode resistance, and three or four pro- grams in the United States, according to Cousins. After developing several phylloxera- resistant rootstocks, grape-breeding programs in North America have shifted their focus from phylloxera resistance to nematode resis- tance. Grape growers in California's San Joaquin Valley now face a bigger problem from root knot nematodes than phylloxera, he said. "But be aware that all rootstocks are not created equally and come in varying levels of vigor and nema- tode resistance," he said. In the past, a few rootstocks offered root knot resistance, though not against virulent populations, and they had other problems or were diffi- cult to propagate. The shift in breeding focus has led to several selections with improved nematode resistance. Potential rootstocks Of nematode-resistant rootstocks recently developed by USDA, he identified three that might have poten- tial for Washington growers—Kingfisher, Matador, and 10-17A. Matador and Kingfisher, which were released in 2010 and are just now becoming available from com- mercial nurseries, offer better root knot resistance than Freedom and Harmony rootstocks. The newer 10-17A, released in 2012, is highly vig- orous and is recommended for the dagger nematode (Xiphinema index), but it hasn't yet been tested for GRADING SOLUTIONS +1/9ÊUÊ, /9ÊUÊ-,6 www.vanwamel.nl Energieweg 1 - P.O. Box 4 6658 ZG Beneden-Leeuwen HOLLAND Tel. +31 (0)487 592944 Fax +31 (0)487 592970 E-mail perfect@vanwamel.nl VAN WAMEL B.V. Your Perfect fruit growing partner for over 65 years! FEEDING s 7ATERDUMPERS s "ULK BIN TIPPERS DISTIBUTORS GRADING s -ECHANICAL WEIGHT s %LECTRONICAL SIZE WEIGHT COLOR EXTERNAL DEFECTS PACKING s 0ACKING BELTS s "AG FILLERS s #USTOM BUILT SOLUTIONS Fruittek Sumas WA 98295 U.S. Packaging Systems Inc. Temple NH 03084 Tel. 877 826 3427 www.fruittek.com Tel. 603 566 9736 www.uspackagingsystems.com Grapes Nematode- resistant rootstocks available Improved rootstocks are available, though more field testing is needed. by Melissa Hansen Peter Cousins shares the names of potential nematode-resistant rootstocks that may work for Washington grape growers.