Updated: June 14, 2021
Symptoms Details Possible causes
Leaf and Flower Spots Spots on leaves or flower bracts; 1/8 inch spots or smaller (spring) Spot Anthracnose (Elsinoe)
  Dark spots on leaves and flower bracts; blighted leaves; causes defoliation (spring) Dogwood Anthracnose (Discula)
  1/4 inch angular spots on leaves (fall) Septoria
  1/4 inch round spots on leaves (fall) Phyllosticta
Leaf and Flower Blights Gray, fuzzy growth on terminal leaves and flowers Botrytis cinerea
  Blighted leaves and flowers, causes defoliation Dogwood Anthracnose (Discula)
Leaf Yellowing Leaves may also have sooty mold Calico Scale
  Leaves may also have sooty mold Cottony Maple Scale
  No honeydew Oystershell Scale
White Coating on Leaves May be on upper and lower surfaces (usually spring only); causes early fall color symptoms (purple/red leaf color) Powdery Mildew
Leaf Wilting Terminal leaves die; swelling on twigs Clubgall Midge
Leaves Browning

Browning leaf edges, leaves drooping, wilting

Drought stress, leaf scorch
Early Fall Color (Summer)

General stress. Peeling, cracked bark near base of tree, brown leaf edges/wilting, purple/red leaf color

Leaf scorch, powdery mildew, drought conditions, poor site conditions (causes tree stress), crown canker
Leaves Eaten or Chewed Sawflies resemble caterpillars (often covered with white powdery material) Dogwood Sawfly
Failure to Flower Begins on lower branches, progresses up into the canopy sometimes Dogwood Anthracnose (Discula)
Twig Dieback Sunken, discolored areas on twigs Branch Cankers
  Twigs may break off Dogwood Twig Borer
  Leaf yellowing and stunting precede dieback Scale Insects, Armored Scale, Soft Scale
  Swelling near branch tips, terminals die prematurely Clubgall Midge
  Leaf blight, defoliation Dogwood Anthracnose (Discula)
Branch Dieback Sunken, discolored areas on twigs Branch Cankers
  Rough, knotty areas on trunk and large branches Dogwood Borer
  Cracked bark near base of young trees, large branch dieback Flatheaded Apple Tree Borer
  Dieback with leaf blight and defoliation Dogwood Anthracnose (Discula)
  Peeling, cracked bark near base of tree Crown Canker

Authors: David L. Clement and Mary Kay Malinoski (retired), University of Maryland Extension Specialists. Revised and edited by Christa K. Carignan, Coordinator, University of Maryland Extension Home & Garden Information Center, 12/2019.