Black Truffle


The grant from the NC Specialty Crops Block grant program was awarded in June 2014; $48,000 over two years. The project ran from April 2015 through June 2017. Here is the abstract for the proposal with the primary purpose highlighted in bold:

There is an established Black Périgord truffle industry in North Carolina. Truffles are a fungus that grows underground in close association with the roots of certain tree species. Black Périgord truffles are valuable, often bringing prices as high as $800 per pound. The North Carolina truffle industry has grown and developed with little assistance from any governmental agencies or universities. There are now growers scattered across the state with a national growers’ (non-profit registered in NC) association, the North American Truffle Growers Association that meets here twice a year to share experiences and discuss the future of the industry. The growers have reached the conclusion that they need to refine their production practices and address a few key problems. Of primary concern is identifying practical and cost-effective methods to ensure inoculated seedlings are inoculated with the proper fungus and to measure the extent of colonization of the Black Périgord truffle fungus in the orchard soil.

In addition to starting the NC State University truffle testing lab, this was the Advice to Growers that resulted from the study (I know this sounds like common sense now, but it was NOT the standard at the time:

As a result of this study, we have new recommendations for Black Périgord  truffle growers in North Carolina. We recommend that they when they purchase trees to plant, they should have a random sample of them DNA tested for the presence of Tmel (or whichever truffle they want to grow) and adequate colonization. Every few years they should test their soil/roots, choosing different trees each time. Careful records should be kept. We do not recommend microscopic examination as a method of determining if their trees are colonized with Tmel, although once Tmel has been confirmed to be the major Tuber species on their roots, they can use that method to monitor the extent of colonization in their orchard.

The grant was awarded to Jeanine Davis at NC State University, but it was clear in the proposal and throughout the project that it was being done in cooperation with the North American Truffle Growers Association. 


The people who worked on the project were:

Jeanine Davis, (Project leader), Inga Meadows (cooperator), Kelly Gaskill, Leonora Stefanile, and Suzette Sharp (former research assistants).


Here is an early website page on the project

Here are the final results as a published research paper

Additional Research

These are the little unfunded studies that we added to our existing orchards in Waynesville:

  • New studies initiated as a result of this project: This project resulted in new collaborations with truffle businesses and other research teams.  It also helped us identify other important issues affecting growers. 
  1. Light study: Dr. Marcos Morcillo from Spain visited us and several of the truffle growers in the state. He questioned the spacing of trees in orchards in the state, including our own research and demonstration orchards in Waynesville. He explained to us that new research indicates that truffle orchards need more light on the orchard floor than our current spacing gives. He suggested that we remove half the trees from our orchard to see if that triggered production (our orchards were established in 2010 and 2013, and although they are well colonized, have not yet produced truffles). Asking a grower to remove trees that cost about $25 a piece and have been lovingly tended for five or more years without proof of concept, is a tough sell. So we agreed to perform the test on our orchards. In spring of 2017 we cut out every other row in both orchards and will monitor the results and report back to the growers at the North American Truffle Growers Association conference. 
  2. Wood ash study: Tmel needs a very high soil pH in order to fruit. Our test orchards have been heavily limed but the soil pH has only reached about 7.5 to 7.6. One of the state agronomists tested our soil again and showed us that all the cation sites on the soil particles were saturated with calcium and that adding more lime would not increase the pH any further. He suggested we try applying wood ash to drive the pH higher. Under his direction, we added wood ash to half of each of our orchards. We will monitor the soil pH and response of the Tmel mycorrhizae in response to it.
  3. Reinoculation study:  Dr. Marcos Morcillo has been experimenting with reinoculation of orchards to bring non-productive orchards into production. A local nurseryman, Brian Upchurch, has started his own truffle business called Carolina Truffles. He entered into a partnership with Dr. Morcillo to offer that reinoculation service here in in the Southeastern US. Before we can recommend such a practice, we need to know if it works here. So in collaboration with Dr. Morcillo and Mr. Upchurch, we reinoculated a number of trees in both of our test orchards.

Jeanine M. Davis, Ph.D.
Associate Professor and Extension Specialist

NC Alternative Crops and Organics Program
Department of Horticultural Science, NC State University
Mountain Horticultural Crops Research & Extension Center
455 Research Drive, Mills River, NC 28759
828-687-0574 (working remotely; please leave msg and I will return your call)

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