Oak Leaf Blister
Blistered Oak Leaves
Oak Leaf Blister Disease
Oak leaf blister, a fungal disease caused by Taphrina caerulescens, is widespread this year on a range of oak species, both in the white oak and red oak groups. Symptoms include raised, blistered, greenish-yellow spots on upper leaf surfaces and darker, corresponding sunken spots on lower leaf surfaces, though sometimes the raised and sunken aspects may be obscured. Fungal growth can sometimes be seen on undersurfaces of leaves.
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Blistered Oak Leaves
Oak leaf blister is a disease is caused by the fungus, Taphrina caerulescens. The fungus overwinters in infected buds and twigs. Leaf infections occur during moist periods in the spring as leaves emerge. Early symptoms appear as raised, blister-like, light-green to yellowish-green spots on the upper leaf surface matched with deep depressions on the lower leaf surface. Eventually, the leaf "blisters" become very apparent as they turn dark brown to brownish-black. The blisters may be evenly distributed across the leaf and are distinct from the angular, vein-based symptoms...