Symptoms of Sick Deciduous Trees

Signs of disease on deciduous trees include leaf spots, premature yellowing or leaf drop, powdery mildew, unusual wilting, and canopy dieback. Other indicators include oozing cankers on the bark, fungal growth (mushrooms) at the base, and abnormal twig growth, such as witch's broom.  Pictured above is an Ash tree with Emerald Ash Borer disease.  

Key Symptoms to Watch For:

• Leaf Issues: Discoloration (yellow, brown), leaf spot pathogens (spots, holes), and powdery white fungus.

• Stem and Branch Dieback: Brittle, dead twigs and branches (test by breaking). Cankers, which are sunken, dead areas on the bark that may weep sap.

• Canopy Loss: Reduced density, with 30% or more leaf loss indicating severe, often irreversible damage.

• Root and Trunk Rot: Mushrooms, bracket fungi, or soft spots on the trunk, indicating internal rot.

• Growth Anomalies: Excessive suckers (new shoots) at the base or on the trunk often indicate extreme tree stress. 

Common Causes:

• Fungal Diseases: Powdery mildew, anthracnose, and leaf spots.

• Bacterial Infections: Fire blight (leaves look scorched).

• Environmental Stress: Drought, waterlogging, or poor soil.

Signs of disease on pine trees include needles turning yellow, brown, or gray is a primary sign of stress, disease, or pest infestation. While pines shed old inner needles in autumn, unusual dropping at other times indicates problems.

• Stunted Growth & Tip Blight: New shoots (candles) in spring may look stunted, yellow, or turn brown/tan, which is often caused by Diplodia tip blight.

• Resin and Cankers: Excessive sap (resin) oozing from the trunk or branches suggests the tree is fighting a disease, such as pitch canker, or is infested with beetles.

• Bark Damage: Holes in the bark, sawdust-like frass (from beetles), or bark peeling away indicates severe insect infestation.

• Branch Dieback: Dead branches, particularly starting from the bottom and moving up, often indicate root disease or severe nutrient issues.

• Fungal Growth: Mushrooms or fungal conks growing at the base or on the trunk suggest root rot or decay. 

Common Causes for Sickness

• Pine Bark Beetle: Small holes in the trunk, often accompanied by red-brown needles and heavy sap flow (pitch tubes).

• Needle Cast/Blight: Fungal infections like Dothistroma or Rhizosphaera cause premature browning and shedding, often with small black spots on needles.

• Root Rot: Often caused by overwatering or poor drainage, leading to yellowing needles and tree instability.

• Environmental Stress: Drought or improper planting depth (girdled roots) can lead to slow decline. 

• If more than 50% of the tree's foliage is brown or red, it may be too late to save it. Consulting a certified arborist is recommended to confirm the cause.