Alder
(Alnus spp.)
The genus Alnus includes about 30 species of deciduous trees and shrubs in North America, Europe, Asia, and parts of South America. The leaves are simple, alternately arranged, and most often serrated. Male and female catkins appear in the spring before the leaves emerge.
Select the Sign/Symptoms below that you are investigating to access the related resource.
Affecting Leaves:
Signs/Symptoms
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Cause: Eriophyid mites
Affecting Stems, Twigs and Small Branches:
Signs/Symptoms
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Cause: Spittlebugs (Clastoptera juniperina)
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Cause: Alder aphid
Affecting Larger Branches or Trunks:
Signs/Symptoms
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Cause: Cytospora canker (Valsa spp.,Leucostoma spp.)