Skip to main content

NC State Extension

Our First Black Truffle Research Project

(Images are in chronological order of oldest to newest)

black truffle
The post below was written in June 2017 when we were in the midst of our first grant funded truffle research project. You can read about the final results of that project in the open source journal Mycorrhiza HERE.
Working closely with the North American Truffle Growers Association, we were awarded a grant to do our first research on black truffles. The study was funded by a Specialty Crops Block Grant administered by the North Carolina Department of Agriculture and Consumer Services.
truffle orchard.
Our truffle growers rely on research and production information from Europe, Australia, and New Zealand. But conditions in the Southeastern US are quite different from those other production areas. Our truffle growers have access to relatively scant region appropriate research and experience.
researcher standing in truffle orchard
The growers identified several research needs that we are trying to address with this project. They want a reliable, practical, and cost effective method to test established orchards for the presence of the particular truffle they want to produce. They would like this verified by an impartial third party. And without this information, a grower could spend many years caring for an orchard that will never produce.
hands holding harvested truffles
The objectives of our project are to determine if Tuber melanosporum is present in the soil. To look for the presence of other fungi and truffles. To determine if we can reliably use microscopic analysis once DNA analysis has confirmed identification. If microscopic analysis is reliable, we will teach growers how to do it.
person collecting samples
We collected samples from seven orchards in late fall and early winter. Two of the orchards have produced truffles. Four of the orchards are expected to produce soon. And one was a newly planted orchard.
person looking at roots under microscope
The roots were separated from the soil and observed under magnification, evaluated for a variety of characteristics, and photographed.
filbert roots under magnification
An example of filbert roots under magnification.
researcher conducting dna analysis
DNA analysis is now being conducted.
row between tree plantings in a truffle orchard
The area close to the trees where little vegetation is growing is known as brule and indicates that the truffle mycorrhizae have colonized the area.
participants attending a field day presentation
Field days are held in the truffle orchard to teach people about the truffle industry, our industry, and the challenges and opportunities for growing truffles in North Carolina.
filbert truffle orchards in April
One of the filbert truffle orchards at the Mountain Research Station in Waynesville, NC in late April.
two filbert truffle orchards, one planted three years earlier than the other
We have two filbert truffle orchards at the research station. The one on the left was planted in 2010 and the one on the right was planted in 2013.
drip irrigation tubing near tree line
Drip-irrigation tubing runs along both sides of the tree row.
evidence of a brule or bare area near base of trees where truffle mycorrhizae are present
If the truffle mycorrhizae are present and becomes well-established, a “brule” appears around the base of the tree. The truffles release volatile compounds that act like natural herbicides. So the brule is a bare area that develops under the trees. This is a good sign that you actually have truffles growing there!
a black Perigord truffle in a hand

A truffle dug from the NC State research orchard in January 2020.

The information above was written as the project was being conducted. The project was completed in June 2017. Advice to growers following the completion of this project:  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 Tuber melanosporum (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 Tuber melanosporum, although once Tuber melanopsourm 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 final peer reviewed, published results of this project can be read here: Link to paper . And as stated above, we now recommend that growers have their soils and inoculated trees tested for the truffle mycorrhizae and other fungi in their orchards. Dr. Inga Meadows offers this service at NC State: Meadows Lab.