You are here

Previously unknown, potentially invasive Armillaria root disease pathogen found in Mexico

Date: December 03, 2014

A fungal species of Armillaria was found causing root disease and mortality of peach trees in Mexico. This species was very different from any previously described species

The figure shows a map of areas where the Armillaria mexicana was found, a middle photo shows an orchard in an infected area, and the third image shows plant mortality
Left: Areas of State of México, México where Armillaria mexicana was found; Center: Fruit orchards established in areas where native, pine-oak forests are cleared; Right: Peach (Prunus persica) mortality caused by A. mexicana. (photos by R.D. Elías-Román


Five photos illustrating Armillaria mexicana mushrooms
Armillaria mexicana. 2. Mature basidiomata (mushroom). 3. Lamellae (gill), stipe (stalk), and annulus (ring-like structure). 4. pileus (cap) surface. 5–6. annulus. 7. lamellae. Bars: 2=5 cm; 3, 4=1 cm; 5=5 mm; 6=1 mm; 7=5 mm. (photos: R.D. Elias-Roman)

Invasive root pathogens are a major threat to forest health worldwide, and the fungal pathogens that cause Armillaria root disease (Armillaria species) impact diverse tree species and are distributed globally. Studies to document the distribution of Armillaria species are essential for assessing potential invasive threats and potential impacts of climate change. Collaborative studies have begun to document the distribution of Armillaria pathogens in Mexico, and a previously unknown Armillaria species was found that represents an invasive threat to other areas.


The fungal pathogens that cause Armillaria root disease (Armillaria species) on diverse tree hosts around the world can act as invasive pathogens when they are introduced to new areas. In many areas, surveys of the native Armillaria species are lacking, so it is difficult to recognize when an Armillaria species is invasive. In recent years, DNA-based diagnostics have allowed for the precise identification of Armillaria species present on a site. DNA-based diagnostics were also used in an ongoing collaborative study with multiple institutions in Mexico to identify Armillaria species associated with root disease in peach (Prunus persica) and other trees Mexico. Most notably, this study showed that a previously undescribed species of Armillaria was causing most of the root disease on peach trees. This previously unknown species was characterized as a newly described species, Armillaria mexicana. This Armillaria species is of great interest because it represents an invasive species threat for many global areas where it is not known to occur.

Fruiting bodies of Armillaria spp.
Fruiting bodies of Armillaria spp.

Continued studies are needed further document its distribution and geographic areas where it represents a potential invasive species threat. A recent study identified a rootstock for peach that is resistant/tolerant to Armillaria root disease caused by A. mexicana.

Key Findings

  • A previously unknown species, which was formally described as Armillaria mexicana, was found causing disease on peach, olive, and oak trees in State of México, Mexico.
  • Armillaria mexicana has not yet been found outside of Mexico, and this species may represent and invasive species threat for other geographic areas with suitable hosts and climate.
  • DNA sequencing was also used to confirm the occurrence of Armillaria gallica, A. mellea, and Desarmillaria tabescens (as A. tabescens) in Mexico.

Featured Publications

Elias-Roman, Ruben Damian ; Calderon-Zavala, Guillermo ; Guzman-Mendoza, Rafael ; Vallejo-Perez, Moises Roberto ; Klopfenstein, Ned B. ; Mora-Aguilera, Jose Antonio. , 2019
Elias-Roman, Ruen Damian ; Medel-Ortiz, Rosario ; Alvarado-Rosales, Dionicio ; Hanna, John W. ; Ross-Davis, Amy ; Kim, Mee-Sook ; Klopfenstein, Ned B. , 2018
Klopfenstein, Ned B. ; Stewart, Jane E. ; Ota, Yuko ; Hanna, John W. ; Richardson, Bryce A. ; Ross-Davis, Amy ; Elias-Roman, Ruben D. ; Korhonen, Kari ; Keca, Nenad ; Iturritxa, Eugenia ; Alvarado-Rosales, Dionicio ; Solheim, Halvor ; Brazee, Nicholas J. ; Lakomy, Piotr ; Cleary, Michelle R. ; Hasegawa, Eri ; Kikuchi, Taisei ; Garza-Ocanas, Fortunato ; Tsopelas, Panaghiotis ; Rigling, Daniel ; Prospero, Simone ; Tsykun, Tetyana ; Berube, Jean A. ; Stefani, Franck O. P. ; Jafarpour, Saeideh ; Antonin, Vladimir ; Tomsovsky, Michal ; McDonald, Geral I. ; Woodward, Stephen ; Kim, Mee-Sook , 2017
Klopfenstein, Ned B. ; Hanna, John W. ; Cannon, P. G. ; Medel-Ortiz, R. ; Alvarado-Rosales, D. ; Lorea-Hernandez, F. ; Elias-Roman, R. D. ; Kim, M. -S. , 2014
Elias-Roman, Ruben D. ; Klopfenstein, Ned B. ; Kim, Mee-Sook ; Alvarado-Rosales, Dionicio ; Hanna, John W. ; Ross-Davis, Amy ; Guzman-Plazola, Remigio Anastacio ; Calderon-Zavala, Guillermo ; Mora-Aguilera, Antonio , 2013
Elias-Roman, R. D. ; Guzman-Plazola, R. A. ; Klopfenstein, Ned B. ; Alvarado-Rosales, D. ; Calderon-Zavala, G. ; Mora-Aguilera, J. A. ; Kim, M.-S. ; Garcia-Espinosa, R. , 2013
Roman, Ruben Damian Elias ; Klopfenstein, Ned B. ; Rosales, Dionicio Alvarado ; Kim, Mee-Sook ; Case, Anna E. ; Ashiglar, Sara M. ; Hanna, John W. ; Ross-Davis, Amy L. ; Guzman Plazola, Remigio A. , 2012
Kim, M.-S. ; Klopfenstein, Ned B. ; Hanna, John W. ; Cannon, P. ; Medel, R. ; Lopez, A. , 2010

Principal Investigators: 
Principal Investigators - External: 
Rubén D. Elías-Román - Departamento de Agronomía - División de Ciencias de la Vida (DICIVA) - Universidad de Guanajuato
Rosario Medel-Ortiz - Instituto de Investigaciones Forestales - Universidad Veracruzana
Dionicio Alvarado-Rosales - Colegio de Postgraduados
Forest Service Partners: 
Mee-Sook Kim, Co-Investigator, Pacific Northwest Research Station
Phil Cannon, Co-Investigator, Forest Health Protection, Region 5
External Partners: 
Amy Ross-Davis, Co-Investigator, Oregon State University
Research Location: