Minor Diseases
Disease Agent Injury Control
J. D. Solomon, F. I. McCracken, R. L. Anderson, R. Lewis, Jr., F.L. Oliveria, T.H. Filer, and P.J. Barry
- Leaf spot, Septoria spp.
- The fungus overwinters on dead leaves; spores are wind disseminated to young leaves in the spring.
- Small round spots with straw colored centers may be numerous; red oaks are preferred; defoliation may result in growth loss but no mortality.
- Powdery mildew, Microsphaera alni and Phllactinia guttata.
- These fungi overwinter on dead leaves, and their spores are spread by the wind to healthy leaves.
- White, powdery mold patches on leaves and buds; leaves may be distorted, stunted and dropped prematurely.
- Twig canker, Dothiorella quercina.
- The fungi overwinter on dead tissues; in the spring, spores are wind disseminated to wounds and twigs.
- Small sunken branch cankers and twig dieback
- Spot anthracnose, Elsinoe, quercus – falcatae
- The southern red oak is preferred host; spreads by wind disseminated spores.
- Very small spots on leaf upper surfaces starting about mid-summer.
- Smooth patch, Aleurodiscus oakesii.
- The fungus survives on the bark surface and releases spores which continues its spread.
- Often regarded as a threat to stand by owner, but it is of minor importance; control rarely needed.
- Iron – deficiency chlorosis
- Iron deficiency may be a common problem with pin and willow oaks in some of the less acid soils.
- Yellow-green discoloration between veins; leaves may curl, turn brown along margins and between veins.
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