Injury to grapevines hit by 2,4-D drift is evident in this photo taken by Michael White of the Iowa State University Extension. Oregon Vineyard Supply announced its plan to stop selling 2,4-D and similar products due to concerns about drift.
—A halt on the sale of popular herbicides prone to drift and damage in Oregon vineyards is the latest move in an ongoing saga regarding the state’s wine industry.
Oregon Vineyard Supply
(OVS) announced this week that it will no longer sell so-called growth regulator herbicides, which mimic the action of natural plant hormones known as auxins. The hormones regulate growth, but when delivered in sufficient concentrations they disrupt biochemical pathways and cause a plant’s death by disrupting apical bud growth and other plant functions.
Among the oldest synthetic herbicides, ester-based formulations have a tendency to volatize and drift into non-target species including grapevines. They’re concerning enough that Washington state has banned the use of high-volatile ester and dust formulations of phenoxy-type herbicides.
Those are among the type OVS has announced that it will stop selling—including 2,4-D, perhaps the best-known phenoxy in the class (it was an ingredient in Agent Orange)—as well as herbicides with benzoic and pyradine compounds as their active ingredients. These include dicamba and the branded herbicides Crossbow and Garlon 4 Ultra.
Amine salt-based formulations of these herbicides tend not to volatize and remain available, though they are often more expensive.
“It’s clear to us through repeated damage year to year that Oregon agriculture is making little progress in addressing this issue,” Matt Novak, president and CEO of OVS, told Wines & Vines
. “Rather than waiting for the Oregon Department of Agriculture to impose some restrictions on products, we thought it was appropriate to be more proactive and voluntarily cease selling these products that are the most notorious offenders.”
Spreading the word
Spraying in the forest sector, which is the largest single user of 2,4-D in Washington state, has long been a concern in Oregon. But damage across the state from herbicide drift has become common enough that earlier this year the Oregon Winegrowers Association
began selling signs asking neighbors not to spray herbicides within 350 feet of vineyards (under the right conditions, these materials can drift up to 10 miles!).
A total of 175 signs have been purchased to date, with one retailer buying 40, a vineyard manager buying approximately 20 for the properties he oversees, and several individual vineyards also stocking up.
“It’s not because growers of any crops are being wilfully ignorant, certainly not malicious, it’s almost always just a simple error—but unfortunately one that can have a significant economic impact for the off-target crop,” Novak explained.
While the substances are covered through training required to earn an applicator’s license, Novak said knowing what to do isn’t the same as doing what you know.
“There’s that gap between taking the test and reading the study guide and actually doing things out in the field.”
Reach of the problem
The point was amply made in a 2010 survey of growers by Oregon State University
associate professor and viticulture extension specialist Patty Skinkis.
The survey attracted 105 participants, of whom 68 reported herbicide damage. Of these, 55% reported that less than 5% of their acreage was damaged.
Where damage was observed, it typically took the form of burned or distorted canopy (44%), reduced canopy growth (37%) and reduced fruit set within clusters (34%).
Approximately 44% of growers spoke with neighbors about the damage to reduce the likelihood of it recurring; 6% spoke to a lawyer and initiated legal action regarding the damage.
But in a trenchant observation, Skinkis noted that self-inflicted herbicide damage isn’t uncommon, especially among newer grape growers. Indeed, 10% of growers admitted to onsite misuse as the cause of the damage they observed.
Another survey respondent reported the in-row application of Triclopyr.
“This is a pyridine herbicide that will cause significant damage to grapevines when applied past bud break,” Skinkis reported. “This same person didn’t report any damage, indicating the possibility that they are unaware of herbicide damage risk and how to identify the symptoms. However, they indicated through the survey that they were aware of neighbors that may cause damage to their vineyard. In cases such as this, the education begins with the vineyard owner.”
This is where OVS hopes its self-imposed ban on sales of the most problematic growth regulators will help.
“OVS will advocate for educating the grower and the applicator with regards to alternative product selection, timing, drift management and other practices and methodologies to prevent the negative impact of growth regulator herbicides on sensitive crops,” the company said in a statement announcing the ban.
It’s “not that what we’re doing is necessarily going to solve the overall problem, because there are other retailers that continue to sell these products, but hopefully it gets people’s attention,” Novak explained.
Since amine salt-based herbicides will be available, Novak doesn’t expect growers will have to go without the tools they need, but he does think it will help all users of the products—from grain growers to grape growers—give deeper consideration to how they control weeds.
“It’s not going to require a major change in the way people farm, or that they do without some necessary tools to solve some of their problems,” he said. “It just requires a slight change in thinking.”