MOB attacks at least 12 species of oaks. In California, it has been found infesting two species of white oak: most commonly valley oak and, to a lesser extent, blue oak. A single, very limited attack was found in a severely distressed California black oak.
Valley Oak
The leaves of valley oak (above) are green, sinuate (alternatively rounded notches and lobes), up to 10 cm (3.9 in) long and up to 6 cm (2.4 in) broad. The leaf margin is smooth. The leaves of blue oak (below) have a blue-green tint leading to the tree's name. Leaves are deciduous, 3.8 cm (1.5 in) to 10.2 (4 in) long, and entirely or partially lobed.
Blue Oak
