Organic fruit and vegetable growers want to meet the recent uptick in national consumer demand, but they need additional tools to battle pests and diseases that often accompany organic crop growth.

One such tool may be the use of essential oils. That’s why the U.S. Department of Agriculture National Institute of Food and Agriculture awarded a nearly $2 million grant to a team of scientists for an Organic Agriculture Research and Extension Initiative project to study the degree to which essential oils can help suppress certain pathogens and pests.

Jonathan Oliver, assistant professor in the University of Georgia College of Agricultural and Environmental Sciences at the UGA Tifton campus, is part of the team of 15 scientists who will work on this project nationwide. Researchers from the University of Florida, Clemson University, the University of California, Riverside, the University of Hawai'i at Manoa and the USDA Agricultural Research Service will collaborate on the project.

In his role as a small fruit pathologist in the Department of Plant Pathology, Oliver will investigate the use of essential oils in organic blueberry production, the state’s top fruit crop.

“Blueberries are the highest value fruit crop in Georgia, and organic blueberry production represents a growing proportion of our total acreage,” said Oliver. “Nonetheless, organic production of blueberries in Georgia faces many challenges, because our hot, humid climate is ideal for many disease issues including fruit rots and leaf spots. Our growers need better tools to help them manage these disease problems.”

Funding for the four-year research program will support scientists with expertise in fruit crop management and physiology, plant pathology, entomology, postharvest biology and organic production.

To carry out the project, scientists will:

• Evaluate the plant safety and horticultural impact of essential oils in managing diseases in fruits including blueberries, peaches, mangos and avocados.
• Begin to test plant disease efficacy claims of essential oil products marketed for organic producers.
• Evaluate organically certified plant essential oils on targeted pathogens such as algal stem blotch, brown rot, scabs, gray mold and powdery mildew.
• Determine the efficiency of essential oils on fruit shelf life through postharvest testing.
• Test the efficacy of essential oils against insects including scales, thrips and mites, although arthropod pests are not the primary focus of this research.

After they gather their new data, participating scientists will communicate the results of their research to organic fruit farmers and those who grow conventional crops, so that those producers can rapidly adopt any new practices. Scientists will also evaluate the effectiveness of the project through continuous feedback from stakeholders.

“Through this research project, we hope to provide Georgia growers with the information they need to make decisions regarding the use of essential oils as a part of their organic fruit disease management program,” said Oliver. “Since Georgia is the largest producer of blueberries in the Southeastern U.S. and one of the top producers in the nation, providing Georgia growers with information and tools for safe and effective organic disease management has the potential to have a broad impact in Georgia and on the Southeastern organic blueberry production industry as a whole.”

Organic food sales topped $50 billion in the U.S. in 2018. Statistics from the Organic Trade Association tell part of the story of this growing market: fruits, vegetables and other specialty crops combined to make up 36.3% of total organic sales, up 5.6% from the previous year.

For more information from UGA about blueberry production, see site.caes.uga.edu/blueberry.

Part of this article was adapted from the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS).