Written By: Emily Cabrera, UGA IPM Communications Coordinator
Expert Source: Andrew Sawyer, Southeast Georgia Area Pecan Agent
This winter researchers will begin a series of trials to help identify better management practices for pecan growers in Georgia. New pecan trees will be planted at the University of Georgia Vidalia Onion and Vegetable Research Center in Toombs County for the purpose of research and demonstration. The research farm consists of two 11-acre tracts that are part of a long-term lease from the Georgia Forestry Commission that provides UGA researchers and staff land to conduct studies and educational demonstrations.
Andrew Sawyer, University of Georgia Cooperative Extension Southeast Georgia Area Pecan Agent, will be spearheading several research projects with a team of UGA researchers looking at various factors that impact the pecan industry, such as variety selection, insect pest management, disease resistance, herbicide application rates, and other input requirements of pecans. Sawyer, who began this new position in May 2019, is based in Statesboro and supports pecan growers throughout Southeast Georgia. The position is funded by the Georgia Pecan Grower’s Association and UGA Extension to provide support to UGA pecan specialist, Dr. Lenny Wells, who is based out of Tifton. This research is funded by a Pecan Commodity Commission grant that was awarded to Sawyer and his team in May 2019.
The team will primarily focus on the effects of pecan scab fungus (Fusicladium effusum) on various cultivars that grow well in the southeast. Pecan scab begins in the tissues of the tree trunk and at bud break in the spring the disease begins to rapidly spread through the limbs, leaves and eventually the nuts. It is the most detrimental disease of pecans in Georgia, causing severe economic losses to the industry each year. Currently, trees must be treated with several applications of fungicides annually in order to produce a marketable crop, as it only takes 25% scab on shucks to minimize quality.
“The most susceptible cultivars to this disease also happen to be the industry standards used here in the southeast,” said Sawyer. Desirable, Pawnee and Stuart are some of the most common and traditional pecan varieties grown in Georgia, valued for their excellent yield and nut quality. Of the three cultivars, growers have shown a preference for Desirable, which has now become the most susceptible variety to the devastating pecan scab fungus.
“We didn’t used to see pecan scab in these cultivars, but over time, as the pecan industry became more or less a monoculture of Desirable, the disease has gained a foothold in orchards throughout the state,” said Sawyer. “We are at a point that we shouldn’t be planting this cultivar in new orchards anymore. There may be some situations where growers are located in more northern areas of the state where this disease isn’t as hard-hitting, but most pecans are grown in warmer parts of the state where spraying from bud break to shell hardening requires an unsustainable amount of labor and money,” Sawyer explained.
Sawyer hopes that through his research program, other low-input, marketable varieties will prove to be just as valuable as the current industry favorites. His recommendation for growers who are interested in establishing new orchards is to use a variety of cultivars to help minimize the risk of disease and pest issues.
“Since 2008, UGA researchers in Tifton have been working with alternative cultivars that are resistant to pecan scab, have low input requirements, are high yielding and produce great quality nuts. Some of the best varieties we’ve seen are Excel, Lakota, Gafford, McMillan, and Kanza – a cold-tolerant variety that may be better suited for growers in north Georgia as well,” said Sawyer.
Low-input cultivars provide an economic benefit to pecan growers, especially in Southeast Georgia, because orchards in this region tend to be managed through commercial practices, but on a much smaller scale than found elsewhere in the state. “When you have a smaller operation, but still have to shell out a lot of time and money into your crop, the cost-benefit ratio sometimes doesn’t work to your advantage. That’s why these low-input cultivars are so attractive, it means growers can save more time and money and end up with a great quality, high-yielding product without all the heavy investments,” explained Sawyer. “So, the Vidalia Onion Research Farm will be a great location in this part of the state to observe these low-input cultivars,” he added.
As research plots are established this winter, trees will be planted in a such a way to accomplish both long-term variety research and short term applied research goals. Sawyer and his team will be hosting several demonstrations at the research farm over the next few years to allow Extension agents and growers to come out to participate in hands-on training events, including planting, pruning, grafting, setting up irrigation, implementing pest and disease prevention strategies, and making herbicide treatments using different chemistries and rotations.
To learn more about pecan management, tune into Sawyer’s monthly radio program at https://soundcloud.com/andrewsawyer-2, or visit the UGA Pecan Blog at https://site.extension.uga.edu/pecan/. To learn more about pecan varieties check out UGA Extension Circular 898. And to download a calendar-based reference guide for annual pecan management, visit UGA Extension Circular 1174.