8 Signs Your Tree Has a Pest Problem

Introduction

A healthy tree is not only a beautiful part of the landscape—it’s also a vital contributor to your local ecosystem. However, even the most established trees in Halesworth and across Suffolk can fall victim to pest infestations. These problems often start small, but if left unchecked, they can weaken the tree, affect nearby plants, and create safety risks.

At Halesworth Tree Surgeons, we help identify and resolve pest problems early—before lasting damage occurs. In this article, we’ll walk you through eight clear warning signs that your tree may have a pest issue, and explain why early intervention is key to keeping your trees safe, healthy, and standing tall.

Key Takeaways

• Pest problems can go unnoticed until serious damage occurs.
  
• Early signs include holes, sticky residue, and canopy thinning.
  
• Prompt action helps prevent tree decline and wider infestations.
  
• Expert assessment and treatment restore long-term health.
  
• Halesworth Tree Surgeons provides professional pest diagnosis and solutions.
  

1. Unusual Leaf Discolouration

Yellowing or browning leaves during the growing season are a clear sign that something is wrong. Pests such as aphids or spider mites damage leaves by feeding on their sap, often causing discolouration before the leaves die and drop.

Watch for:

• Patchy yellowing or dark spots
  
• Leaves curling, drying out, or dropping early
  
• Discoloured veins or patterns on the leaf surface
  

2. Tiny Holes in Trunks or Branches

Small, round holes are usually the entry or exit points for boring insects like bark beetles or moth larvae. These pests dig into the wood, weakening the tree from within and potentially introducing fungal infections.

Look for:

• Clean, round or oval holes in the bark
  
• Fine sawdust (frass) around the base
  
• Bark that feels soft or hollow in places
  

3. Thinning Canopy

If your tree’s crown is looking sparse or patchy, it could indicate pest activity that’s affecting the tree’s ability to produce and retain healthy leaves.

Signs include:

• Noticeably thinner foliage than in previous years
  
• Reduced growth on branches or tips
  
• Sections of the crown with dead or dying limbs
  

4. Sticky Residue or Black Sooty Mould

Certain sap-feeding insects secrete a sugary substance known as honeydew. This attracts fungal growth and can leave a sticky, black coating on leaves and bark, which in turn blocks sunlight and reduces photosynthesis.

You may notice:

• Leaves with shiny or sticky surfaces
  
• Black mould growing on leaves or stems
  
• Increased presence of ants or wasps
  

5. Unusual Bark Damage or Cracking

Pests can cause or worsen cracks in bark, especially when they burrow beneath the surface. Damaged bark may also weep sap or become misshapen.

Check for:

• Cracked, peeling, or sunken bark
  
• Unexplained lesions or damp areas
  
• Evidence of tunnelling under the bark
  

6. Birds or Wildlife Focusing on One Tree

A sudden increase in woodpecker activity or animals digging around the roots may signal that insects are living inside the tree. Birds often feed on larvae, giving you a helpful clue that pests are present.

Indicators include:

• Repeated pecking in the same area
  
• Stripped bark or nesting holes
  
• Damage to surrounding soil or roots
  

7. Lumps, Galls, or Deformed Growth

Some insects trigger the tree to form abnormal growths, commonly known as galls. These can appear on leaves, twigs, or bark and may affect the tree’s ability to grow and reproduce normally.

Look for:

• Swollen or knobbly growths on stems or leaves
  
• Warts or blister-like deformities
  
• Distorted leaf shapes or curled shoots
  

8. General Decline in Tree Health

When a pest problem becomes established, your tree may show broader signs of stress. These often develop slowly, but they point to deeper issues that require attention.

Symptoms may include:

• Reduced spring growth or late leaf emergence
  
• Dry or brittle branches, especially at the crown
  
• Overall weakening of structure or stability
  

Conclusion

Pests are a common but serious threat to trees, especially when left undetected. Recognising the early warning signs can make the difference between saving a tree and losing it altogether. At Halesworth Tree Surgeons, we specialise in identifying pest-related issues and providing the right treatment to restore tree health and prevent further damage.

If you’ve noticed any of the symptoms listed above, don’t wait for things to get worse. Contact us today for a professional inspection—and let us help protect the trees that make your property so valuable.

Call us on: 01508 505 537
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