As the beetles attack the tree, the attacking beetles, the tree oozes out resin that will dry into white or reddish popcorn-sized globs visible on the tree’s trunk. These are a good indicator of beetle infestation. This “ooze” looks like small, yellow gummy-shaped sap formations, called pitch tubes.
Fine, powdery red-brown dust around holes on tree bark.
Foliage that changes to a dull green, then yellow and finally a reddish-brown.
- The pitch is accompanied by a sawdust-like substance, called frass, created by bark beetles and their larvae as they borethrough the bark.
- Frass generally falls to the ground, resembling very fine, saw-dust-like granules at the base of the tree.