Leaves Stems/Twigs/Smaller Branches	ALDER - Alnus spp. AFFECTING LEAVES: CONDITION CAUSE Beadlike galls on both sides of leaf surfaces Eriophyid mite AFFECTING TWIGS AND SMALLER BRANCHES: CONDITION CAUSE Frothy spittlemass Spittlebugs (Clastoptera juniperina) Cottony material Alder aphid AFFECTING LARGER BRANCHES OR TRUNK: CONDITION CAUSE Discolored areas, dead bark containing small pimple-like fruiting bodies Cytospora canker (Valsa spp., Leucostoma spp.)
Missoula County Extension Office; Missoula, Montana 59808 - Updated for 2006