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researchers examine pine boughs exhibiting needle blight

The research team members shown examining infected pine boughs are from left to right Joseph Fan, associate professor of forest ecology and statistics; Lana Narine, assistant professor of remote sensing and modeling; Lori Eckhardt, team leader and professor of forest health, J. Ryan Mitchell, former forestry regional extension agent with the Alabama Extension System, and Janna Willoughby, assistant professor of population and conservation genetics.

It appears first as small brown spots surrounded by a yellow halo, splattered across loblolly pine needles like a chemical spill. And then it spreads.

Brown spot needle blight is an increasing threat to pine forests, but a research team in Auburn University's College of Forestry, Wildlife and the Environment is working to find solutions.

Through a $2.1 million U.S. Forest Service grant, Lori Eckhardt, a professor of forest health, and her team members in the college—Joseph Fan, associate professor of forest ecology and statistics; Lana Narine, assistant professor of remote sensing and modeling; and Janna Willoughby, assistant professor of population and conservation genetics—are aiming to determine the impacts on productivity and biological causes of needle blight.

Insect pests and fungal diseases are an urgent concern to the forest industry. Costs associated with damage caused by non-native pests and pathogens within U.S. forests in 2000 were estimated at approximately $4.2 billion annually.

The Alabama Forestry Commission (AFC) has received phone calls since the spring of 2022 from landowners and the public reporting brown pine needles on previously healthy trees. Many of these calls came first from counties in Alabama's northwest and northeast regions. The disease has since been confirmed in 36 of 67 Alabama counties.

Historically, the needle blight has only infected longleaf pines, or Pinus palustris, but in the last few years, the disease has also begun to infect loblolly pines, or Pinus taeda, in young and mature stands.

researchers examine pine boughs infected with brown spot needle blight

Discolored needles are the first sign of infection. Over time, the infected area turns brown with a dark red or dark green border. The discoloration begins in the lower portion of the crown and moves up as the disease spreads by rain and wind events. An easy way to identify the disease is if the pine needles look like they have been scorched by fire, even though there has been no burn.

The cause for this change in behavior of the disease has yet to be determined, but researchers speculate that a new sub-species has evolved from the original fungal pest, according to the AFC.

“An investment in mitigating forest pests, such as those associated with needle blight, requires adaptive management geared to prevention and remediation that provide economically sound solutions,” said Eckhardt, team leader, CFWE professor of integrated forest pathology and entomology and director of the Forest Health Cooperative.

Their research may help landowners and forest managers predict future timber revenues from affected stands more precisely and adjust management activities accordingly.

pine forest along roadside infected with brown spot needle blight

“We hope to determine the distribution and movement of the needle pathogens, determine if their appearance is due to more aggressive strains and understand the disease cycle and the environmental factors that drive their emergence and distribution,” said Eckhardt. “Non-native pests and pathogens may not only occur on a large regional scale, but also on isolated acreages. This is vital, as the majority of the seven million acres of pines in Alabama are privately owned.”

According to the Alabama Cooperative Extension System, the Alabama forest industry contributes more than $25 billion to the state’s economy. The sustainability and profitability of these pine forests and industrial wood plantations rely on optimal tree growth. However, the continued introduction of non-native insect pests and fungal pathogens, as well as the movement of native forest pests into forest ecosystems, can result in significant economic impacts.

Another team member with the Alabama Extension System will assist with the project's outreach component.

“One of the roles for extension during this project is to create publications on the research that is being conducted and get that information out to the landowners and citizens of Alabama,” said Eckhardt. “They will provide workshops to train the trainers and teach others about the brown spot needle blight, how to identify it, the ecology and different management techniques.”

Since the project launched, CFWE has held several workshops to share current assessments of brown spot needle blight. Professionals from the Southeast have shared potential methods to manage the disease and how it may vary from state to state. Expert presentations have included identification, mitigation, genetic diversity and environmental factors.

“The knowledge produced by Eckhardt and her team will be used to develop best management practices for areas affected by needle blight,” said Janaki Alavalapati, the Emmett F. Thompson Dean of the College of Forestry, Wildlife and Environment. “It will also help direct future research actions, especially when little is known regarding the impact of the pests and pathogens associated with loblolly pine in the southeastern United States.”

Landowners are encouraged to contact their local AFC office if their pines are infected with brown spot needle blight. Symptomatic needles can be collected and brought to the Forest Health Dynamics Laboratory at Auburn University for confirmation.

Media contact: Jamie Anderson, College of Forestry, Wildlife and Environment