A bug that's smaller than a pinhead can do serious damage to trees and for the first time it's been spotted in Indiana.
The Indiana Department of Natural Resources says walnut twig beetles carrying a fungus that causes Thousand Cankers Disease (TCD) has been detected in Yellowwood State Forest in Brown County.
Infected walnut trees usually die two or three years after they show symptoms. The fungus from the beetle creates a canker, or dead area, under the tree's bark.
The plantation in question has been quarantined, which means black walnut can't be moved out of the forest.
None of the trees currently show any symptoms.
Black walnuts are the most valuable trees in Indiana. DNR says there are an estimated 31.5 million walnut trees in Indiana. The agency says it would be a $1.7 billion loss if all black walnut trees were lost because of TCD.