Silver Maple

(Acer saccharinum)

Silver Maple is a fast-growing shade tree commonly planted in Colorado, but it is prone to structural weakness, chlorosis in alkaline soils, and several pests and diseases including borers, scale, leaf scorch, and fungal leaf spots.

Seasonal Pest & Disease Calendar

Problem Type Active Season
Aphids Insect Spring–Fall
Scale insects Insect/scale Spring crawlers; visible year-round
Maple borers Insect/borer Summer
Verticillium wilt Fungus Spring–Fall
Anthracnose / leaf spot Fungus Spring–Summer
Leaf scorch Abiotic Summer–Fall
Chlorosis Abiotic Spring–Summer

Pest & Disease Guide (Homeowner-Friendly)

Aphids

Common symptoms
  • Sticky honeydew
  • Sooty mold
  • Leaf curling
Treatment & management
  • Rinse foliage
  • Encourage beneficial insects
  • Treat severe infestations

Scale Insects

Common symptoms
  • Hard or cottony masses on bark
  • Yellowing leaves
  • Branch dieback
Treatment & management
  • Treat crawler stage
  • Horticultural oil
  • Prune infested areas

Maple Borers

Common symptoms
  • D-shaped or round exit holes
  • Boring dust
  • Branch dieback
Treatment & management
  • Reduce stress
  • Deep watering
  • Preventive treatment if needed

Verticillium Wilt

Common symptoms
  • One-sided wilting
  • Brown streaking in wood
  • Rapid decline
Treatment & management
  • No cure
  • Prune affected limbs
  • Support overall tree health

Anthracnose / Leaf Spot

Common symptoms
  • Brown blotches along veins
  • Distorted leaves
  • Early leaf drop
Treatment & management
  • Remove infected leaves
  • Improve airflow
  • Usually cosmetic

Leaf Scorch

Common symptoms
  • Brown leaf edges
  • Crispy margins
  • Early fall color
Treatment & management
  • Deep watering
  • Mulch base
  • Reduce heat stress

Chlorosis

Common symptoms
  • Yellow leaves with green veins
  • Stunted growth
  • Canopy thinning
Treatment & management
  • Iron treatments
  • Improve soil conditions
  • Adjust watering

When to Worry vs. When It’s Cosmetic

When to Worry (action recommended)

  • One-sided rapid decline (possible wilt)
  • Borer holes in trunk or limbs
  • Large branch cracking or splitting
  • Heavy scale infestation
  • Severe chlorosis with dieback

These issues often require professional arborist evaluation.

Mostly Cosmetic (monitor only)

  • Light leaf spotting
  • Minor aphid activity
  • Slight scorch after heat
  • Occasional early leaf drop
  • Small patches of scale

These typically resolve with proper watering and seasonal changes.