Pines Dying from Bottom Up: Normal Needle Drop vs. Bark Beetles

NW Ohio: Scotch pines died; now mature Norwegian pines browning from bottom up. Malathion spray didn’t help.

Diagnosis Check

If branch tips green, brown needles interior → normal seasonal needle drop (pines keep 2–3 years of needles).
If all needles brown → tree dead, likely bark beetles (not fungicide-treatable).
Bagworms on arborvitae are separate issue.

Photo of trunk/foliage needed for certainty. Few diseases cause bottom-up death. Bordeaux mix not indicated without confirmed fungus.

Trees: Managing Pine Needles in the Landscape: From Nuisance to Resource; Cutting White Pine Boughs for January Wedding: Timing and Storage; Pine Needle Management: Leave, Rake, or Mulch?; Lightning-Struck Pines: Fatal Diagnosis and Professional Assessment; Cedar Needle Drop and Cedar-Quince Rust: Normal vs. Action Needed; Pine Needle Loss on Interior Branches: Natural Aging; Sudden Tree Death: Need Species ID to Diagnose; Construction-Damaged Pines in Florida: Call State Forester; Saving Indoor Palms in Dry, Heated Homes: Humidity, Watering, and Repotting; Identifying Fir vs. Spruce and Normal Inner Needle Drop

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