Botanic Garden >> Gardening > >> Question and Answer >> About Gardening

Maple Trunk Turning Black: Gloomy Scale Infestation

Black maple trunk? That's sooty mold on honeydew from gloomy scale—pinhead-sized insects blending into bark.

Identification

Tiny bumps on bark (1/16-1/8 inch).
Scratch with fingernail—they flake off.
Black sooty mold accumulates over years.
Often undetected until trunk blackens.

Treatment (Professional Recommended)

Dormant season: Horticultural oil spray (thorough coverage).
Mid-summer: Insect growth regulator for crawlers.

Why Hire an Arborist

Large trees need high-pressure equipment for canopy coverage. Timing is critical for crawler stage. Arborists have proper products and application methods.

Images

maple gloomy scale

About Gardening: Black Spots on Sugar Maple Trunk: Borers or Bleeding Canker?; Sugar Maple with Black Trunk and Holes: Sapsucker Activity; Red Maple Black Oozing: Phytophthora Bleeding Canker, Complex Management; Red Maple Borer Infestation: Sap Flow and Bud Failure; Black Trunk on Young Sugar Maple: Normal Bark Maturation; Silver Maple Trunk Rot: Don't Foam—Fertilize and Prune Deadwood; Maple Borer Infestation in Old Wound: Treatment and Risk; Planting Hybrid Maples Near Black Walnut: Juglone Tolerance; Best Mulch for Mature Maple Trees; Co-Dominant Trunks in Maple: Why Early Correction Prevents Future Failure

Garden Articles

Black Spots on Japanese Maple Bark: Likely Harmless Lichens

Black Spots on Maple Leaves: Tar Spot Fungus—Rake Leaves, Reduce Inoculum, Tree Usually Fine

Slime Flux (Wet Wood) on Maple Trees: A Bacterial Condition

Dealing with Borer Damage in Crimson Maple Trees

Borers in Young Maple; Lilac Decline

Maple Planted Too Deep: Fatal Flare Burial

Maple Trunk Wound: Planting Too Deep, Mulch Volcano, Grass Competition

Plants

Black Lines in Lightning-Struck Maple Wood: Lightning Trace Scars—Fascinating Wood Feature

Sunset Maple Decline: Premature Color, Leaf Spots, and Trunk Issues

Maple Tree Black Eggs: Gall Mites, Not Eggs

Maple Tree Limb Crack with Larvae: Remove Limb, Treat Borers

Black Trunk on Live Oak: Natural Aging or Lichens?

Maple Tree Black Ooze: Slime Flux (Wetwood)—A Mixed Blessing

Maple Trunk Split: Wound Healing and Borer Prevention