1. UC IPM
Dark staining of walnut around the entrance and exit holes made by walnut twig beetle, <i>Pityophthorus juglandis,</i> a symptom of thousand cankers disease, caused by <i>Geosmithia morbida.</i>.
Dark staining of walnut around the entrance and exit holes made by walnut twig beetle, Pityophthorus juglandis, a symptom of thousand cankers disease, caused by Geosmithia morbida..
Credit: Elizabeth J. Fichtner