Park Alert...

Deer Vomit!

April 2021

By Ranger Amy

Grapevine with orange slime running down it

When the weather is wet and temperatures cool, you might see a bright orange slime on muscadine grapevines. Is this deer vomit or some sort of excrement from a wild animal?

Some locals call it deer vomit. But it’s actually a wild yeast, Fusicolla merismoides, that is naturally present on the leaves, branches and fruit of wild grapes.

When a grape vine is injured it will leak sap to clean its wound. Sap contains water and carbohydrates, food for the yeast. Cool, but not cold, temperatures make perfect growing conditions for this fungal yeast, forming the orange slime.

This fungus does not need to be sprayed or managed in any way since it won’t harm the grapevine.