WSDA resumes traps to watch for moths that harm grape fields

The Washington State Department of Agriculture has resumed setting traps to detect any presence of four species of moths destructive to grape fields, according to the Washington Association of Wine Grape Growers (WAWGG).

The statewide watch list are the European Grapevine Moth, the European Grape Berry Moth, Grape Tortrix and Grapevine Tortrix, with Yakima, Benton, Franklin and Walla Walla counties getting closest scrutiny.

The moths have caused problems in California. To date, none have been detected in Washington State.

WAWGG praised the state for its continuing monitoring.

The Associated Press filed a report on the monitoring.

Here’s the full text of the WAWGG news release:

The Washington State Department of Agriculture continues to protect the second-largest grape-growing state in the U.S. and the number two producer of premium wines by continuing its cooperative program with the U.S. Department of Agriculture in looking for four species of destructive moths (European Grapevine Moth, European Grape Berry Moth, Grape Tortrix, and Grapevine Tortrix).

Up to 1,000 traps are being placed this month for each of the four moth species around the state, between late May and July, according to Mike Klaus, WSDA entomologist and survey coordinator for Eastern Washington.

Traps will be placed in most of the 13 major wine grape growing regions. Trappers will focus on vineyards and will also target backyard grape vines near potential pathways of pest introduction. Klaus said the traps will be checked every two-to-four weeks during the summer and then taken down in September. Similar WSDA surveys conducted the past two years yielded no detection of the pests.

“Our trappers will have state identification and welcome any questions landowners may have,” Klaus added. “We’ll be trapping from the San Juan Islands to the Columbia Gorge to Okanogan, but our emphasis will be in Yakima, Benton, Franklin and Walla Walla counties.”

The European grapevine moth was found for the first time in the U.S. in 2009 in Napa Valley, a serious threat to California’s wine industry. After its initial detection in Napa Valley, the pest has been found in several other counties. Some California growing regions are under quarantine.

In 2013, the U.S. Department of Agriculture’s Animal & Plant Health Inspection Service (APHIS) released $16.9 million in emergency funding to prevent the spread of European grapevine moth in the Golden State.

If any of the four species of targeted moths are found in the Evergreen State this summer, state agriculture officials may place more traps in the area in an attempt to find the center of the infestation. Officials say they would also consult immediately with state and federal agencies to determine the best course of action, as well as reach out to industry stakeholders.

“We greatly appreciate the focus of the grape pest survey from WSDA,” said Vicky Scharlau, executive director, Washington Association of Wine Grape Growers. “The damage potential from these pests, and all pests and diseases, is a huge concern to us and we have to stay vigilant or pay the price.”

Klaus emphasized that none of the moth species have been detected in Washington.  “The goal of the survey is to protect Washington’s grape industry by preventing the establishment of these invasive moths,” Klaus said. “We want to detect them as early as possible if any do arrive. If any of these grape pests were to become established here, they could pose a serious threat to our grape and wine industries.”

WSDA will also resume a limited survey for grape phylloxera, an aphid-like pest that attacks grape roots. Washington State University and WSDA have detected grape phylloxera at a few locations in Eastern Washington vineyards and backyard grape plantings back in as recently as 2002.

Grape phylloxera is considered to be the most serious grape pest worldwide, especially on vinifera grapes.  California growers have experienced significant losses, sometimes requiring the removal and replanting of entire vineyards. WSDA has cooperated with WSU several times over the last 25 years in survey for grape phylloxera. However, in Washington, official surveys for the pest have not been conducted since 2002. The control of grape phylloxera is costly and is only achieved after many pesticide applications over several years. Planting resistant rootstocks has been the primary control measure. However, new biotypes in California are known to attack previously resistant rootstocks. Washington vineyards may be vulnerable since they are planted on their own nonresistant roots.

In the mid-1990s, a new pest of grapes, the vine mealybug, was found in California. WSU entomologist, Dr. Doug Walsh, has been conducting limited survey for vine mealybug along with research on another established mealybug species, the grape mealybug. To date, vine mealybug has not been detected in Washington.

WSDA has a quarantine in effect for both grape phylloxera and vine mealybug to prevent these threats, to the Washington state grape and wine industry, from spreading.