Fig. 13.

Tubakia californica, symptoms on infected California black oak (Quercus kelloggii) trees in Tuolumne County, CA. A. Early spring growth showing healthy new leaves and infected brown leaves still hanging from the previous season. B. Current season foliage with angular lesions developing near the leaf margin and progressing along the leaf veins. C. Symptomatic branch showing necrotic lesions on the new growth as well as old, infected brown leaves that did not abscise and presumably served as the primary inoculum source. D. Progression of foliar symptoms from healthy leaves (top left) to leaves with small black veins, to leaves with more prominent black veins along the midrib and larger necrotic areas to completely brown leaves. Bar (C, D) = 10 cm.