Grapevine Pathology on the Central Coast with Dr. Shunping Ding

Contributed By Beka Dunaway, Ben Shinkwin, & Felipe Vallejo | AGC 470 students

The California Central Coast is known for its leading role in agriculture and tourism, more specifically, the multitude of wineries and vineyards that call San Luis Obispo County home. Most people may only think about winemaking or sipping the product in a tasting room, but Dr. Ding’s research impacts the growing operations of winegrapes.

Dr. Shunping Ding is an assistant professor in the Wine and Viticulture and Horticulture and Crop Science departments at California Polytechnic State University, San Luis Obispo. She is a microbiologist and plant pathologist who studies grapevine diseases and plant disease management on the Central Coast.

Dr. Ding is a researcher in plant disease diagnosis, plant pathology, and the detection of fungicide resistance in pathogens at California Polytechnic State University, San Luis Obispo. She gained interest in pursuing plant pathology as a child due to her plant ecologist father's work in the forest in China. She has a B.S. in Biological Sciences from Henan University, China, a Master of Philosophy in Microbiology from The University of Hong Kong, and a Ph.D. in Plant Pathology from the University of Wisconsin-Madison. She has four published research papers in peer-reviewed publications. Through her three main research projects, she emphasizes and supports the ultimate practices of sustainable agriculture. Sustainable agriculture includes a system that is environmentally sound, economically viable, and socially just.

"It's about the sustainability of agriculture.

How are you going to manage the disease, in what way?"

Dr. Ding's first research project is identifying and treating a deadly complex called Trunk Disease. There are a number of pathogens identified so far, such as pathogens in the genera of Eutypa, Botryosphaeria, and Diplodia. This disease causes the vines to decline in production and threatens the longevity of the vineyard. It is very hard to identify and people do not know which pathogen causes the disease on their specific plant. Dr. Ding's research is on finding the pathogen responsible for this disease and trying to figure out which ones are more prevalent in the Central Coast.

"I’m taking samples from vineyards all over the Central Coast to see what pathogen is causing the trunk problem to study those prevalent pathogens."

The second project that Dr. Ding is working on is the study of Powdery Mildew. This is a severe disease that can occur to all green tissues of grapes, including berries. The infection may lead to berry spitting and alteration of wine characteristics.

The pathogen that causes Powdery Mildew can be reproduced many rounds every season, which means that growers need to spray fungicides multiple times in order to manage the disease. Fungicides are biological organisms used to kill parasitic fungi or their spores.

"Now the growers are using a single-site mode of action fungicides to target specific parts of the pathogens. This makes them less harmful to non-targets. With a specific target of the pathogen, fungicide resistance can accumulate rapidly if the fungicide is applied repetitively."

The spraying of fungicides is meant to be as similar to a natural process as possible. Dr. Ding stated that "the more times the grower sprays, the higher selection pressure they put on the pathogen.”

Another study that Dr. Ding is working on is the study of how fungicides can lose their efficacy over pathogens. She says that "over time the population, the resistance portion is becoming dominant, and that's when the fungicide will lose its efficacy". To study this area of resistance, Dr. Ding collects Powdery Mildew pathogens from all over the Central Coast and sees if the pathogen population carries the mutation that confers the fungicide resistance. Then, she will give the information to the growers to assist them in better fungicide selections.

These are incredibly important research studies on the Central Coast, which is home to hundreds of wineries and family-owned businesses reliant on the health of grapevines and other crop plants.

Dr. Ding's main key message to the public is the importance of sustainable agriculture. She is passionate about making sure growers and winemakers know the impact of managing and mitigating fungicide resistance. She stated that, 

"It’s also important to know what fungicide the pathogens are resistant to so you don’t overspray and waste resources." 

​Dr. Ding is considerate of the grower's economic stability, as well as passionate about maintaining a sustainable practice of agriculture.

Dr. Ding's future plans include a few projects. Dr. Ding and her students will be working on Botrytis bunch rot and management and will again be a mentor for the summer research program that occurs every summer at Cal Poly. Dr. Ding continues to be excited for not only her research but the possibility of sharing it with the scientific and agricultural community.

If you are interested in learning more about how Powdery Mildew is affecting the Central Coast wine industry, click here.