Grape Field Day Focuses on WSU’s Research into New Ways to Spray
The Washington State Grape Society and Washington State University hosted a field day on August 11 focused on WSU’s vineyard technology research, particularly in the area of spray technology.
WSU graduate students shared their findings on two very different types of pest control: designing better application techniques for traditional chemicals and alternative spraying approaches that would eliminate residues.
In the old bullring, Jake Schrader shared his experience trying to develop a system for applying heated horticultural oil to improve its pest control properties and using ozone to fight mold and scale insects. The challenge with both is that under field conditions the droplets are unable to pack the promised punch by the time they hit the leaves. The ozone loses its concentration almost immediately and the heated droplets cool quickly.
Another more promising alternative is ultraviolet light therapy. By firing a box full of high-intensity UV bulbs at rows of vines in the dark of night – when powdery mildew cannot repair cell damage caused by light exposure – researchers can provide a significant control, said Lexie McDaniel. Now they’re trying to figure out how producers could best implement it.
“Every three days is probably the ticket to controlling mold, but that comes with labor issues,” she said, compared to much longer intervals for traditional fungicides. “It’s promising, but it needs more integration.”
On the more traditional chemistry front, Ramesh Sahni explained how WSU is working with precision spray technology to help airblast sprayers adjust output in response to canopy size. Commercially available technology from Smart Guided Systems can help vineyards apply more than 40 percent less chemicals while achieving the same level of biological control and less off-target drift, he said.
Finally, biological systems engineer Lav Khot introduced the group to WSU’s new spray drone. The technology was developed with row crops in mind, he said, and doesn’t have the flight time or payload to do open-field applications. However, he is trying to see how he could have precision application possibilities in vineyards, such as spraying border rows for mites or targeted applications of nutrients and beneficial insects.
The field day also provided an opportunity for Camilo Acosta of the Washington State Department of Agriculture to update Yakima Valley grape growers on the state’s efforts to eradicate Japanese beetles, which have were first detected in Grandview in 2020 and subsequently trapped in alarming numbers in this local area. Last year.
The good news for grape growers is that Japanese beetles don’t like grape berries, but grape leaves are one of more than 200 potential hosts. This is an important distinction, because while the state prepares to enact a quarantine that would prevent the movement of beetles from the infested area, it will not impact the transportation of harvested grapes. Corn, hops and yard waste, however, will be subject to transportation restrictions, such as WSDA trapping or on-site processing, during the adult beetle’s active season from May through October, Acosta said. Meanwhile, potted plants, compost and topsoil are a problem all year round.
The invasive pest is primarily trapped in residential areas, where the state treated more than 1,000 acres of lawns earlier this year. Acosta said it was a good start, but his team was only able to reach about half of the owners in the affected area targeted by the control program.
The bad news is that a homeowner in Wapato, about 30 miles from the known infestation, reported finding the beetles in grapes in his garden in late July. Traps set up there had caught more than 70 beetles by the first week of August, Acosta said. Another oncoming detection, in Richland, resulted in no additional captures.
These results show how important quarantine is for preventing hitchhiking. “He didn’t steal from Wapato, he didn’t steal from Richland,” Acosta said.
Despite this spread, he is optimistic about the state’s plan of attack.
“Even though we found these beetles in Wapato, we are still in eradication mode,” he said.
—by Kate Prengaman