Napa County vineyards host pioneering drone tests

Vineyard Drones in Napa

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[Editor’s Note: Brittany Pederson, a viticulturist and pest control adviser, sees drones replacing some backpack spray operations.]

This summer, the tending of Napa Valley vineyards has gone airborne.

A pair of vineyards in Oakville and Calistoga have become testing beds for an unmanned, remote-controlled aircraft that can spread pesticide, fertilizer and other substances on steep and difficult-to-reach fields. Silverado Farming Co. Inc., the Napa-based vineyard management company, plans to continue the tests next year in partnership with the Yamaha Motor Corp., which hopes to make its RMAX drone available to U.S. farmers starting in 2018.

A loosening of federal licensing rules for unmanned aircraft has widened their use in numerous businesses this decade, but Silverado Farming’s tests – which will determine their effectiveness in combating a vine-attacking fungus – appear to be the first crop spraying by licensed drones at a commercial U.S. farming operation.

At least five other vineyard management companies in the Napa Valley have contacted Yamaha for possible testing of the RMAX, a remote-controlled helicopter that has been used in Japan, Australia and other countries since the late 1990s, according to spokesman Brad Anderson. The company plans to eventually offer its drones as a service to U.S. farmers, with Yamaha employees piloting and maintaining the aircraft, whose operators require a pilot’s license.

From April to August, Silverado used the drone to deliver fungicides to grapevines, comparing its effectiveness to existing methods of dispensing chemicals from vine-row tractors or backpack sprayers, said Brittany Pederson, a company viticulturist and pest control adviser. The chemical protects vines against powdery mildew, which attacks both the leaves and grapes of infected plants.

Each vineyard was sprayed eight times at two-week intervals, with vines getting either airborne and ground-based spraying on the same days.

Early evaluations point to the usefulness of aerial spraying on highly sloped farmland, according to Pederson, adding that many recently planted lands far from the valley floor may benefit the most.

“I think the Napa Valley has lot of small vineyards and steep hillsides that are difficult to apply chemicals and I think they would be a good fit,” she said Wednesday, referring to growing operations placed farther up the valley to take advantage of unique weather and soil conditions.

In Calistoga, the Yamaha drone also has been tested over non-trellised vine rows whose late-season growth makes it difficult to move workers and heavy equipment in and out without damaging the plants, according to Pederson.

“I see it being a fit not necessarily in replacing (ground-based spraying) in whole, but replacing some backpack spray operations during the season,” she said. “Labor is a huge issue, so if we can spare some of our labor force from the difficulty of these backpack sprays, that would be a great benefit.”

First developed by Yamaha in the 1990s, the RMAX, which weighs 220 pounds when fully fueled, contains two tanks within its 9-foot-long, 2 ½-foot-wide frame. Nozzles connected to the tanks can dispense pesticide, seed, fertilizer and other materials, and the drone can stay aloft for up to 50 minutes at a time.

Yamaha began testing the RMAX locally in 2012 at the Oakville Experimental Vineyard, an Upvalley research station owned by the University of California, Davis. In addition to servicing rougher terrain, the unmanned aircraft potentially could spread substances at up to 10 times the speed of tractors and hand sprayers, UC Davis professor Ken Giles said during an Oakville demonstration in October 2014.

In 2015, the RMAX became the first unmanned aircraft to win certification from the Federal Aviation Administration for agricultural flights, the FAA’s website says.

On Monday, the FAA relaxed licensing rules for lightweight drones under 55 pounds, allowing operators to pass a written test and pay a $150 fee rather than get a pilot’s license.

Some 2,100 companies and individuals have federal permission to fly drones for farming, according to the drone industry’s Association for Unmanned Vehicle Systems International. Farmers have used the aircraft for surveying, thermal and infrared scanning to track soil moisture and crop changes, and keeping track of broken water lines and other irrigation problems.

Information from The Associated Press was used in this report.


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