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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #109079
Title: STATUS AND PROGRESSION OF INFESTATIONS AND MANAGEMENT OF THE GRAPE PHYLLOXERA IN THE PACIFIC NORTHWEST, USA

Author
item Fisher, James
item HELLMAN, EDWARD - OSU, CORVALLIS, OR

Submitted to: International Proceedings Symposium on Grape Phylloxera Management
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: This paper discusses the present status and the spread of the worldwide number one economic insect pest of grapes (grape phylloxera) in the Pacific Northwest. Included are methods being taken to alleviate and prevent damage by this pest in the same region. Presently, there are three infested sites in Central Washington and 42 sites in Oregon. These numbers sare important since in 1990 there were only 8 sites in both states. This pest has cost the state of California over one billion dollars in damage over the past decade. The rapid spread that has been seen in Oregon could have the potential to severely affect the half a billion dollar wine industry in the Pacific Northwest. The only defense against this pest is to have wine grapes grafted to resistant rootstock. Unfortunately, 2/3 of the acreage in Oregon and all of the acreage in Washington and Idaho are planted with non-grafted vines. A survey conducted in 1999 of affected vineyards in Oregon found that many growers are doing little to contain this pest and most are looking for temporary remedies to the situation so that they can postpone replanting with grafted vines (a cost of nearly 30 thousand per acre). Adding soil components that promote vigor in the plants appears to give growers a margin of time to recoup potential losses.

Technical Abstract: The grape phylloxera, Daktulosphaira vitifoliae Fitch, has been present on Vitis spp. in the state of Washington for more than three decades and in commercial wine grape vineyards in the state of Oregon since 1990. For both states there are nearly 11,000 ha planted to European wine grape varieties; ~10,000 ha are self-rooted. More than another 8000 ha are planted with juice grape varieties. Three vineyards potentially affecting < 30 ha were found to have grape phylloxera in Oregon in 1990. By 1995 the number had risen to 14 vineyards. Presently, 42 vineyards have been infested. This means that >700 ha are immediately affected, but, there is the potential for spread to at least 4 - 5 times that amount. Contrarily, the three sites in Washington that are affecting about 15 ha of Vitis labrusca (Concord grapes) have not spread to nearby (~4 km) wine grape vineyards. In 1999 we surveyed Oregon owners as to history of infestation, age of vines, varieties, cultural practices and avenues they are taking fo remedy. Pinot noir is the most affected variety. Most Oregon vineyards average <10 ha and are on high value land. Major replanting is not the usual practice, however, replanting with rootstock in small blocks and interplanting are most common methods of combating this pest. Others are using foliar nutrient applications and a few are using drip irrigation while keeping the infested plants. Pre-1997 infestations tended to be located in vineyards that were ~11 yr. old. Post-1997 infestations tended to be located in vineyards 6-9 yr. old.