HARDWOOD LEAF DISEASES OF
mildew, caused by Microsphaera spp., Phyllactinia spp. and others.
These fungi overwinter on dead leaves. Spores are windblown to healthy
white, powdery mold occurs on leaves and buds. Leaves may be distorted,
stunted and fall prematurely.
blister, caused by Taphrina spp. This fungus overwinters on bud
scales. When buds expand, infection of new leaves occurs. Spores
produced on leaves are disseminated by wind.
to purple blisters appear on leaves. Blistered leaves remain on
spots, caused by various fungi. Fungi overwinter in leaf tissue;
spores are disseminated by wind and rain.
round to angular spots, variable in size and color appear on leaves.
Defoliation may occur in extreme cases.
deficiencies. These physiological conditions are soil related. Soil
condition, such as pH, may make nutrients unavailable to plants,
or the soil may be exhausted of some nutrients.
tissue turns yellow to brown; often this happens first along the
veins. Some leaf fall may occur. Dieback may occur later if uncorrected.
for Urban Trees
- Rake and destroy
fallen, infected leaves.
- Maintain high
vigor through cultural practices.
- Control with chemical
- Control with appropriate
There are EPA registered
chemicals for the control of these leaf diseases. Consult a specialist
if the damage appears to be unusually severe and chemical control is needed.
Leaf blister on oak.