Stunted grapevines are a big concern for growers, and they often assume pests such as rust mites are to blame.
But that’s not always the case, according to Oregon State University Viticulture Extension Specialist Patty Skinkis.
“They [growers] had coined a term, ‘Short Shoot Syndrome,’ that we later linked to rust mite feeding, but not all vineyards have stunting due to this pest,” she says. “We wanted to break that association of stunting with a single pest.”
To do so, Skinkis and her colleagues developed an Extension publication and coordinating app outlining various abiotic and biotic factors that can cause stunted vine growth. She says the publication and app are unique because they look at problems based on symptoms, rather than many other Extension guides, which outline symptoms associated with a single pest or disease.
“This publication and app is one of the first that is an information tool that works backwards from the symptom,” she says.
The interactive app works by providing indexed information that allows growers to navigate through different causes and symptoms to help narrow down the possible issues they’re having in the vineyard. A photo gallery is provided that allows growers to zoom in on pictures to see if the symptoms might be comparable to what their vines are experiencing.
“But we caution the heavy reliance on pictures, as they are just an example, and there can be different symptom expression across multiple vines or a whole vineyard,” Skinkis says.
Once growers have downloaded the app, they don’t need an Internet connection to access it, which is beneficial to those who might have poor mobile service in the field, she adds.
Ultimately, Skinkis hopes the information provided in the publication and app will help growers more accurately determine the cause of their stunted grapevines and treat them accordingly, rather than just spraying.
“The premise under which the content for the Extension guide and associated app was developed was to avoid having growers assume that the stunting is due to microscopic rust or bud mites and apply a pesticide to control a pest that may not be present and/or may not be causing the symptoms,” she says.
For growers who do not have a smartphone, the information is available in an online PDF.