Study: Remote Sensing of Weeds on Vineyards Has Merit

Aerial Sensing Of Weeds Saves Time and Labor

By Jessica Theisman, Associate Editor

There is a potential use of remote sensing with drones and vineyard weed management. Working on that research is Cody Drake, a senior at California State University, Fresno. He’s working with Luca Brillante, an assistant professor in the Department of Viticulture and Enology. Anil Shrestha is chair and professor, also in the Department of Viticulture and Enology at Fresno State. Drake’s research is at a vineyard in Napa County.

“The goal of my research is to make weed management practices in vineyards a little more efficient,” Drake said.

Currently, there is a lot of manpower, money, and time going into scouting for weeds and spraying.

“What we did with the drone is we wanted to map high-pressure weed zones to target spray in the field instead of spraying the entire field,” Drake explained.

This aerial scouting is hoping to become more efficient for time and labor.

“It’s all based on imagery. The drone gives us waypoints as to the areas where we need to spray. We have a company that’s called Drone Deploy, and they go through, and they stitch all the photos together,” Drake said.

Drake’s research has only been on vineyards so far, and his research has been proven to work.

“We did a 30-meter flight and a 10-meter flight, and that just shows the difference in how close you can get to identifying weeds species on the ground at a 30 meter height,” he said.

At 30 meters, it was very hard to tell which species was which. At 10 meters, the weeds were more identifiable.

“We would prefer to do another trial with a higher resolution camera. That way we can see the species, identify them a little easier and a little more efficiently,” Drake said.

By doing this, Drake and his team can pinpoint where the heavyweights are and just go spray that one area. For future research, they are going to try a camera with higher resolution to see if it can see through a denser vineyard.

Forest Fires Could Be Impacting Winegrapes

Smoke Taint Could Cause Off-Flavor Vines

Many forest fires throughout California have been near or upwind from many winegrape vineyards and could be causing problems for the grapes.

Jim Kennedy, a professor and chairman of the Department of Viticulture and Enology at the California State University of Fresno, explains a particular serious problem due to smoke enveloping vineyards.

“A lot of these fires are getting very close to the wine industry, and that’s a problem because the smoke that these fires generate, they come in contact with clusters of fruit. The compounds that are smoke get absorbed onto the fruit and the plant likes to modify these compounds, because it can be quite toxic to plant cells,” said Kennedy. “The wine gets made from that fruit and the wine ages, the smoke compounds become released again, and it’s a real problem. Your wine starts to resemble an ashtray, its smell and character,” he added.

Kennedy said the tragedy is that the fruit is exposed to the smoke and it’s not readily and obviously upfront as problematic.

“A winemaker goes through the wine-making process thinking their fruit has escaped the problem, and low and behold a year down the road its become an ashtray. And that is something as the grape and wine industry we’re really keeping an eye out on these forest fires, and consulting with winemakers in these different regions so they are aware that this is a potential issue,” said Kennedy.

Kennedy said that this problem, also known as “smoke taint” has been seen many times.

“The classic sample is Australia. With the bush fires in Australia a lot of the vineyards are very close to eucalyptus groves, and so there’s a lot of research that has come out of Australia in terms of how to measure the potential for smoke taint in fruit and how to deal with it once you got it. The Australians tend to be on the front-end of it because it’s an issue that has much more potential for disaster in their industry,” said Kennedy.