Moniliophthora roreri causes frosty pod rot disease in cacao. The disease damages the cacao pods, rendering the seed useless. Yield losses of close to 100% have been recorded (e.g., 90% in Venezuela, 95% in Ecuador) and in many cases entire plantations have been abandoned once struck with the disease. Moniliophthora roreri is the sister species to M. perniciosa which is the causal agent of witches’ broom disease of cacao, another devastating disease of the crop.  Moniliophthora perniciosa is a mushroom-forming fungus, producing a fruiting body typical of the Marasmiaceae.  However, M. roreri has never been observed to produce a fruiting body, reproducing solely by the production of billions of conidia on the surface of infected cacao pods. The main goals of our research in this area are to understand the reproductive biology and life history of M. roreri and to provide better information to ultimately aid in developing effective control strategies. 

 

 

Pathogens of cacao

 

Typical symptoms of frosty pod rot on cacao pods. Image from Aime and Phillips-Mora (2005) and reproduced with permission from Mycologia

Twenty-one day old culture of M. roreri; brown coloration is due to the massive production of conidia. 

Tetrapyrgos sp. photographed in Brazil, representing a typical mushroom-forming member of Marasmiaceae.

 Select Publications

 

  • Aime MC, Phillips-Mora W. 2005. The causal agents of witches’ broom and frosty pod rot of cacao (chocolate, Theobroma cacao) form a new lineage of Marasmiaceae. Mycologia 97:1012–1022. doi: 10.3852/mycologia.97.5.1012

  • Amoako-Attah I, Shahin AS, Aime MC, Odamtten GT, Cornelius E, Nyaku ST, Kumi-Asare E, Yahaya HB, Bailey BA. 2020. Identification and characterization of fungi causing thread blight diseases on cacao in Ghana. Plant Disease. doi: 10.1094/PDIS-03-20-0565-RE

  • Crozier J, Thomas SE, Aime MC, Evans HC, Holmes KA. 2006. Molecular characterization of endophytic morphospecies isolated from stems and pods of Theobroma cacao. Plant Pathology 55:783–791. doi: 10.1016/j.mycres.2008.01.008

  • Diaz-Valderrama JR, Aime MC. 2016. The cacao pathogen Moniliophthora roreri (Marasmiaceae) possesses a tetrapolar mating system but reproduces clonally. Heredity 116:491-501. doi: 10.1038/hdy.2016.5

  • Díaz-Valderrama JR, Leiva-Espinoza ST, Aime MC. 2020. The history of cacao and its diseases in the Americas. Phytopathology 110: 1604–1619. doi: 10.1094/PHYTO-05-20-0178-RVW

  • Diaz-Valderrama JR, Aime MC. 2016. The cacao pathogen Moniliophthora roreri (Marasmiaceae) produces rhexolytic thallic conidia and their size is influenced by nuclear condition. Mycoscience 57:208-216. doi: 10.1016/j.myc.2016.01.004

  • Meinhardt, LW, Rincones J, Bailey BA, Aime, MC, Griffith GW, Pereira GAG. 2008.  Moniliophthora perniciosa, the causal agent of witches’ broom disease of cacao: What’s new from this old foe? Molecular Plant Pathology 9:577–588. doi: 10.1111/j.1364-3703.2008.00496.x

  • Niveiro N, Ramírez NA, Michlig A, Lodge DJ, Aime MC. 2020. Studies of Neotropical tree pathogens in Moniliophthora: A new species, M. mayarum, and new combinations for Crinipellis ticoi and C. brasiliensis. Mycokeys 6:39-54. doi: 10.3897/mycokeys.66.4871

  • Phillips-Mora W, Aime MC, Wilkinson MJ. 2007.  Biodiversity and biogeography of the cacao (Theobroma cacao) pathogen Moniliophthora roreri in tropical America. Plant Pathology 56:911–922. doi: 10.1111/j.1365-3059.2007.01646.x

  • Phillips-Mora W, Cawich J, Garnett W, Aime MC. 2006.  First report of frosty pod rot (moniliasis disease) caused by Moniliophthora roreri on cacao in Belize. Plant Pathology 55:584. http://www.ndrs.org.uk/article.php?id=012041

  • Phillips-Mora W, Ortiz CF, Aime MC. 2007. Fifty years of frosty pod rot in Central America: Chronology of its spread and impact from Panama to Mexico. Proceedings of the 15th International Cocoa Research Conference, Vol. I. Pp. 1039–1047.