PASCO — Nate Roberge wrestled a white, tent-like trap into position Monday on the wires of a trellis, hiding it behind the leaves and grape clusters in a Pasco vineyard.
The Washington State University Tri-Cities viticulture and enology student is helping set 1,800 traps for four moth species in vineyards in Benton, Franklin and Walla Walla counties.
The traps are meant to act as an early warning system for four species of moths that have the potential to significantly harm the state’s grape and wine industries.
The invasive moths will chow down on grapes or grape leaves if they manage to sneak into the state. So far, the state doesn’t have them, and that’s the way state officials and farmers want to keep it.
“We hope we don’t find them,” said Michael Klaus, an entomologist with the Department of Agriculture. “But if we do, we want to find them as soon as possible.”
Detecting the pests early is key and gives the state and its farmers a shot at decimating them before they set up a permanent population.
“We greatly appreciate the focus of the grape pest survey from WSDA,” said Vicky Scharlau, executive director of the 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.”
With about 800 licensed wineries, Washington is the second-largest U.S. producer of premium wines. The wine industry’s economic impact in Washington was estimated at $8.6 billion in 2011, according to the state wine commission.
The moths being hunted are the European grapevine moth, European grape berry moth, grape tortrix and grapevine leafroller tortrix.
The European grapevine moth and grapevine leafroller tortrix feed on the leaves and the clusters of fruit, Klaus said. The European grape berry moth eats the fruit and can introduce a mold that causes even more damage to vineyards. The grape tortrix also eats the grapes.
Of those, the highest priority is European grapevine moth because the pest already has invaded California, he said.
Statewide, about 4,000 traps will be set, Klaus said. Those traps will be set at least 70 feet apart so they don’t interfere with each other. The traps release pheromones to attract the males of the specific moth species, Klaus said. The moths lured in get stuck in a sticky substance and will be sent to the state’s moth lab in Olympia for testing. The traps are checked every two weeks into September.
Each moth is smaller than a dime, so microscopes are needed to determine what the traps actually caught, Klaus said. They end up catching quite a few “non-target” moth species.
In addition to the moths, officials will look for evidence of an aphid-like pest called grape phylloxera, which feeds on roots, injecting its saliva into them, causing a reduction in yield and possible death to grapevines. Grape growers have asked the state specifically to look for that pest this year, Klaus said.
Roots will be taken from some vines from vineyards that volunteer to participate so they can be tested for the pest, he said.
Industry officials said grape phylloxera is considered the most serious grape pest worldwide. It’s costly and takes multiple years to eradicate. California growers have removed and replanted entire vineyards because of the pest. The last surveys for grape phylloxera in the state were in 2002.
The grape pest survey program is being paid for using the recently approved federal farm bill. WSU entomologists and the Washington State Association of Wine Grape Growers also partner with the state on the project.
Because of limited funding, Klaus said the state rotates where traps are laid. Some sort of surveying for grape pests has occurred off and on for the last 30 years.
