Identifying and Combatting Vascular Diseases in Trees

Vascular diseases pose a significant threat to tree health. If not properly managed, it can lead to tree death. Vascular diseases pathogens include fungi, bacteria or viruses that infect a tree through its vascular system. The vascular system is responsible for transporting water and nutrients to the tree. The diseases disrupt the flow of these essential nutrients, thus leading to eventual tree death. Learning how to tackle vascular diseases in trees helps protect your clients’ landscapes and ensure the longevity of their investments. 

Identifying Signs of Damage

Understanding these diseases and their symptoms is essential when protecting your customers’ trees. Common vascular diseases include Dutch elm disease, oak wilt, and verticillium wilt. These occur in trees with a vascular system like elm, oaks, maples, and sycamores. The most common signs of vascular disease are wilting, leaf discoloration, branch dieback, and stunted growth. Symptoms for these diseases may only occur on one part of the tree so remaining vigilant can prevent the disease from spreading. Symptoms can also be identified internally. Pruning an infected branch or trunk will reveal discolored vascular tissue. The infecting pathogen causes this staining and can either be brown, black or green. 

Prevention and Control Methods

The best way to combat vascular diseases are to prevent it from ever affecting your clients’ trees. The best practice for preventing diseases is proper tree health. Ensuring your customers’ trees have sufficient water, nutrients and healthy roots is vital to fending off diseases. Using a deep watering technique encourages the roots to grow deeper into the soil, increasing the tree's stability. 

Strong care practices like proper fertilization and pruning are also crucial for preventing diseases. Cleaning tools thoroughly between uses prevents cross-contamination. Removing all debris and sap and cleaning thoroughly scrubbing with soap and water is a start. Disinfecting tools with a proper solution is the key to killing any pathogens.

Insects can also spread and transmit pathogens. Using insecticides or traps can prevent them from attacking your customers’ trees. Bark beetles, ambrosia beetles, two-lined chestnut borers, and spotted lanternflies are the most common insects to look out for. Avoid mechanical damage when using lawn equipment around trees to prevent creating entry points in the bark. Installing protective barriers like tree guards or mulch rings will help keep mowers and trimmers at a safe distance.  Document detailed records of tree health and treatments to track disease progress and the effectiveness of interventions. 

If the symptoms of vascular disease start to occur, control measures need to be taken to avoid tree death. Remove and properly dispose of infected branches to prevent spreading to nearby trees. The easiest way to do this is by pruning 12 to 18 inches below the infected limb. Making clean cuts just outside the branch collar without leaving stubs will prevent diseases. Also, avoid scheduling pruning during extreme weather conditions to avoid tree stress. Increasing the amount of water intake can also help stop the spread of disease. The trees most often plagued with vascular diseases are the ones already stressed. This can slow the progression of the disease and give you time to prune and discard infected branches. Some vascular diseases are terminal. If the tree continues declining after treating symptoms, the tree should be removed and destroyed to prevent further contamination of the landscape.

By being informed about these diseases and recognizing symptoms you can protect and care for your clients’ landscapes. A proactive approach saves trees and enhances the reputation and success of your business. 

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