How to Treat Diseased Trees: Best Practices

Learning how to treat diseased trees starts with recognizing the signs of disease. In this post, Ray’s Tree Service, Sanford’s professional tree service, discusses common tree diseases and how to deal with them.


This common fungal infection affects tree leaves in North America. You’ll see leaf spots on the leaves before they drop off unseasonally. You’ll also see dense packs of shoots.  

You should remove the infected leaves, flowers, and twigs quickly and use a copper-based fungicide. 

Apple Scab 

Apple scab attacks crab apples as well as apples. The fungus causes ugly lesions on the fruit and leaves. It’s a mild disease that looks worse than it is. 

You can treat it by removing the infected foliage and fruit. It’s also helpful to use fungicides proactively at the beginning of summer. 

Canker Diseases

These diseases are either bacterial or fungal in origin. You must take cankers seriously because they cause structural damage. The tree becomes brittle, making its branches and twigs fall off easily. 

Proactive management is better than trying to find a cure. If you do see an infection, deal with it immediately by removing diseased wood. 

Cedar-Apple Rust 

Another fungus, Cedar-Apple Rust is relatively mild, but it weakens the tree. It only affects Apple or Crabapple trees and Eastern Red Cedars.  

You can control a mild infection by removing the growths that release the spores. You can also apply a liquid copper or similar fungicide. 

When learning how to treat diseased trees, there is always one rule. Whether dealing with cankers or powdery mildew, start treatment immediately and consider getting professional help. 

Diplodia Tip Blight 

This fungus is a blight to grown conifers, especially those under significant stress. Your best protection against this fungus is to keep the tree healthy by feeding the soil. You can also consider planting your trees in sheltered positions, as exposure to extreme weather may stress the trees.  

Unlike other fungi, this infection is difficult to spot because it consists of small black growths. They appear on the needles or pine cones and are easy to miss unless you look for them. 

You must remove the infected sections and spray the tree with a fungicide. 

Dothistroma Needle Blight 

This disease impacts pine trees. You’ll notice the needles browning and then dropping off, eventually leading to tree death. This usually occurs on the lower sections of the tree but can spread. 

You can prevent this with a proactive treatment in spring when the buds start and a second dose after the needles grow to full size. 

Fire Blight

Fire Blight is common in pears and apples. It’s a bacterial infection that attacks the blooms, reducing fruit production. However, it causes cankers as it spreads, and this results in shoots wilting. 

You cannot cure it, so your best bet is to prune the cankers out when the tree is dormant. An anti-bacterial spray may help to slow the spread. 

Contact Us for the Best Advice

Now that you know how to treat diseased trees, look into warning signs you should remove a tree. For more assistance, call Ray’s Tree Service at (407) 326-4019 to schedule a visit. 


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Ray's Tree Service is happy to provide complete tree services in Sanford, Florida and the surrounding areas. We offer all kinds of tree services to meet your needs. We have been the region’s top-rated tree care company year after year because of our high-quality execution and competitive pricing. If you’re in need of fast and dependable tree services, give Ray's Tree Service a call!

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