North Carolina’s Christmas tree industry supports about 850 growers and their businesses, employing thousands of people in the state, mostly in WNC’s High Country. These businesses account for a total annual revenue estimated between $250 million and $400 million, not including greenery production like wreaths or other products crafted from the trees.

With Christmas trees representing a significant impact on WNC’s agriculture industry, mitigating the increasing negative impact of Phytophthora root rot disease is of the utmost concern, according to NC State’s Christmas Tree Genetics Program Director Justin Whitehill.

Working with growers as well as NC Department of Agriculture’s Mountain Research Station, Whitehill takes note of arising concerns and keeps this sector’s leaders abreast of the latest issues, which widely involve Phytophthora. Other concerns growers have shared include the prevalence of an insect called the Elongate Hemlock Scale, which causes regulatory issues for exporting trees to other states. Increasing deer populations in areas like Ashe County create problems for growers during winter months, when deer can eat new buds off multiple acres of trees.

The Christmas Tree genetics lab maintains a Frasier Fir breeding program which takes trees from the wild and searches for those which have a higher tolerance to pests and pathogens. The program works to increase tolerance among tree populations using molecular and genomics tools to enable farmers to reduce the amount of growing time while helping trees to resist damaging pests.

“Our main focus is trying to mitigate the impacts of diseases and pests because that’s becoming the primary challenge for growers,” Whitehill said. “In the late 1990s, there was only one Phytophthora species causing disease in trees. There were six species found in 2014, but now, that total has increased to 11 species that can cause disease, and the end result is always that the trees die."

The best available solution is grafting young Frasier Firs with the root stock or a more resistant species from Japan. As the plant fuses together, the roots resist pests while still producing the desirable tree. Water runoff management is also an important tool in decreasing Phytophthora occurrences, especially toward the bottom of mountainsides and in valley areas which tend to have wetter soil.

Whitehill is also conducting research on the Japanese species to understand its resistance with a hope of discovering genetic information that could be translated into Frasier Firs. As Japan is very strict on exportation of plant material, the potential ability to edit the DNA in the States could be impactful to the industry.

“It takes 25 to 30 years to get one rotation of genetic improvement because with the biology of conifers, that’s how long it takes to produce cones and pollen,” Whitehill said. “We’re trying to speed up that process using genomic tools to predict how the trees will perform in the field by looking at their DNA. There are also possibilities of propagating thousands of trees in a petri dish with prescreened genetics. The only route to save the species from the disease is probably finding something to put into its DNA to protect it, and we’ve got to protect this industry in North Carolina.”