Two related species of fungi love chocolate so much they might ruin it for the rest of us.

 

Witches’ broom, caused by the fungus Crinipellis perniciosa, and frosty pod rot, caused by Moniliophthora rorei, kill cacao plants, whose seeds are used to make chocolate, from the inside out. Together they are the two greatest threats to the world’s chocolate supply.

 

Despite being notorious cacao plant killers, relatively little was known about the two fungi, making them even more difficult to control. Now, Cathie Aime of the USDA’s Agricultural Research Service has used DNA analysis to determine that these two culprits are close relatives, information that scientists could use to help protect cacao plants.

 

Witches’ broom lives inside cacao plants and causes it to randomly send out deformed, broom-like shoots. Frosty pod is a mold that covers cacao pods – where the cocoa seeds are found. The image above shows a pod affected by frosty pod. The inset in the upper left shows the inside of a healthy pod.  

--Bjorn Carey

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Credit: Scott Bauer/USDA ARS