Spruce, Blue
Symptom Cause  
Foliage looks bad, small cocoon-like silken bags hang from twigs
Bagworms
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When young potions of foliage disappear, or young tips disappear; shredded bark on trunk
Deer
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Tree misshapen; lower branches dead
Old Age
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Gnawed tree bark
Rodent Injury
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Needles discolored; undersides blistered
Rust (on plants)
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Small caterpillars, usually in high numbers, grouped together, foliage being eaten
Sawflies
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Leaves stippled, yellowing or bronze; dry out and drop may be webbing visible; sometimes galls form on leaves
Spider Mites
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Needles and buds eaten out; defoliation
Spruce Budworm
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Cone-shaped galls on twig tips
Spruce Gall Aphids
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Needles webbed together; larvae mine the needles, which eventually turn brown.
Spruce Needle Miners
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Branches die; needles drop; cankers in bark
Twig Blight
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