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United States Department of Agriculture

Agricultural Research Service

Research on cacao pathogens (Moniliophthora spp.): frosty pod rot and witches’ broom
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cross section of healthy cocoa podThe two most devastating diseases of chocolate (Theobroma cacao) in tropical America are caused by the fungi Crinipellis perniciosa (witches’ broom disease) and Moniliophthora roreri (frosty pod rot or moniliasis disease). Crinipellis perniciosa belongs to a large order of basidiomycetes, the euagarics, which contains few known pathogens, while M. roreri was once widely believed to be an anamorphic ascomycete. Both fungi are indigenous to tropical South America. Together these diseases have caused relatively recent devastation to major cacao-farming regions in South and Central America, and are responsible for the plummet in tropical American cocoa production.  Despite the socio-economic and environmental impact of these fungi, aspects of their life cycles, including mode of reproduction, genetic variability and phylogenetic relationships have not been resolved.

The objective of this research is to:

  • Define systematic relationships for important basidiomycete pathogens, especially of cacao and crops of tropical origins.
  • Elucidate aspects of biology that will directly impact ability to predict patterns of disease and to effectively control their spread.

The phylogenetic placement and evolutionary history of the chocolate pathogens Moniliophthora roreri and Moniliophthora perniciosa (= Crinipellis perniciosa)  have been resolved. The results continue to impact the international breeding and biocontrol programs for cacao.

Agricultural Research article (October 2005): Fungal Threats to Cocoa Share an Ancient History


Last Modified: 6/27/2007
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