Fungal disease threatens pine plantations in Arkansas – UAM’s Arkansas Forest Health Research Center fights back

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August 20, 2025

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Brown spot needle blight is a fungal disease that infects pine needles, leading to premature needle loss, stunted growth and long-term stress that increases a tree’s vulnerability to other pests and pathogens.

Forest health experts from the University of Arkansas at Monticello have identified brown spot needle blight on loblolly pine in 11 additional counties in Arkansas this year, bringing the total number of confirmed counties to 25.

Brown spot needle blight is a fungal disease that infects pine needles, leading to premature needle loss, stunted growth and long-term stress that increases a tree’s vulnerability to other pests and pathogens. While it has historically been associated with longleaf pine, Pinus palustris , in the grass stage, over the past several years it has mainly affected loblolly pine, Pinus taeda , of all ages and size classes.

“The infection is characterized by needles forming brown spots with a yellow halo, crown discoloration, and progressive needle damage and loss that can, after multiple years can lead to tree death, but this is a slow process,” said Laura Sims, director of the Arkansas Forest Health Research Center and associate professor of Forest Health at UAM. “Still, the disease is very concerning because it is now widespread across the loblolly pine producing area.”

Temperature, humidity and rainfall patterns have a large influence on the pathogen's growth, spread and infection process. Most of the infections occur during the rainy season, particularly from late spring through early summer.

Doubling down on spore production

“Fall spore production has been observed at some sites in southeast Arkansas and south-central Louisiana, Mississippi and Alabama, extending the dispersal period to twice a year in some locations, and speeding up the disease progression,” said Sims.

Along with her research technicians and forestry student workers, Sims has been monitoring and identifying outbreaks of brown spot needle blight across the Southern region with a focus on Arkansas.

Brown spot needle blight was first confirmed in Arkansas in 2020, with detections in Garland and Saline counties. The disease continued to spread in subsequent years, appearing in Grant, Hot Springs, Howard, Montgomery and Sevier counties in 2021; Pike County in 2022; Ashley, Drew and Lincoln counties in 2023; and Chicot, Perry and Union counties in 2024. The 11 newly identified counties in 2025 include: Bradley, Calhoun, Clark, Cleveland, Columbia, Dallas, Hempstead, Jefferson, Lafayette, Nevada and Ouachita.

Beyond Arkansas, the disease has also been confirmed on loblolly pine by other experts in Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee and Texas. The most significant damage, including some tree mortality, has been reported in Mississippi, Arkansas, Alabama and Louisiana.

Seeking a way to slow the spread

Through the Arkansas Center for Forest Health Research, Sims and her team are continuing to study the pathogen and explore practical, science-based measures that forest landowners can take to help slow the spread of the disease. Her research is being conducted in collaboration with the Arkansas Department of Agriculture , the Louisiana Department of Agriculture and Forestry and the U.S. Department of Agriculture’s Forest Service .

Some of the research teams current studies focus on preventative measures that can be taken with established pine stands and seedlings. Sims stated that thinning of our forest is a vital key to forest health; however, the current market is not favorable for these practices.

“It would be very helpful if we had more places to take pulpwood — it could slow further spread of the disease. Through proper management, pine stands can become more vigorous,” said Sims. “Timely thinning and prescribed fire won’t stop all the current mortality, because the disease process is relatively slow and already well underway. But I think we can reduce future disease pressure. There is so much loblolly on the landscape right now that is ripe for harvest, but there are not enough markets, so the disease continues to spread and amplify.”

Forest landowners and managers who suspect brown spot needle blight on their property are encouraged to contact Sims at simsl@uamont.edu . For more information about brown spot needle blight, visit the Arkansas Forest Health Research Center’s webpage and FSA 5037, "Emerging Brown Spot Needle Blight Disease on Loblolly Pine".

Diagnosing the disease

Diagnostic samples may also be submitted to the center. Samples should be placed first in a paper lunch sack, then sealed inside a one-gallon plastic bag. Each sample should be clearly labeled with the sample name, date of collection, collector's name and the location of collection (GPS coordinates if available). Ship samples overnight in a sealed box to:

Dr. Laura Sims University of Arkansas System Division of Agriculture, Forestry 110 University Court #3468 Monticello, AR 71656