As a board-certified Master Arborist, my career is dedicated to the health and preservation of trees. One of the more devastating ailments I frequently encounter in my practice is the bleeding canker, often caused by a group of pathogens known as Phytophthora. These pathogens, which are not true fungi but oomycetes, wreak havoc on our beloved trees, leading to significant damage and, in severe cases, death. Let’s dive into the intricacies of Phytophthora infections and explore how we can mitigate these threats to our green canopy.
Understanding the Enemy: Phytophthora
Phytophthora species are notorious for their ability to infect and damage a wide range of host plants, with trees being particularly vulnerable. The interaction between these pathogens and tree tissues is complex and destructive. The infection usually targets the bark and cambial regions, vital for the tree’s growth and nutrient transport.
The cambium layer, responsible for producing new growth, and the phloem, which transports sugars, are severely affected. As the pathogen proliferates, it destroys these essential tissues, leading to the characteristic bleeding cankers. These cankers are not merely wounds but are indicative of deep-seated infection and systemic damage.
The Bleeding Canker Phenomenon
Bleeding cankers are a distressing symptom for any arborist or tree enthusiast. They manifest as dark, oozing wounds on the tree’s bark, releasing a sticky fluid composed of sap, water, and defensive compounds produced by the tree. This fluid is a telltale sign of the tree’s battle against the invading Phytophthora species.
Integrated Management Strategies
Managing Phytophthora bleeding cankers requires an integrated approach, combining cultural, biological, and sometimes chemical methods. Here are strategies I recommend based on my experience:
1. **Environmental Modification**: Ensuring proper drainage around trees is crucial. Phytophthora thrives in wet conditions, so improving soil drainage can significantly reduce the pathogen’s impact.
2. **Cultural Practices**: Keep the tree’s surroundings clean and free from debris. Pruning infected limbs with sterilized tools can help prevent the spread of the disease.
3. **Biological and Chemical Controls**: While biological control options are being explored, fungicides may be necessary in severe cases. However, these should be used as a last resort and applied according to environmental guidelines to avoid adverse effects on non-target organisms.
4. **Regular Monitoring**: Early detection is key. Regular inspections by certified arborists can identify potential infections before they become severe, allowing for timely and effective interventions.
A Final Word
The battle against Phytophthora and its resulting bleeding cankers is ongoing. As arborists, it’s our duty to stay informed about the latest research and management strategies to protect our trees. Through diligence, science-based management, and a commitment to tree health, we can mitigate the impact of these devastating pathogens.
Preserving our trees requires a collective effort from arborists, tree owners, and the community. By understanding the enemy and employing effective management strategies, we can ensure that our trees continue to thrive for generations to come.
My Best,
Matt Latham – 713.385.7040
ISA Board Certified Master Arborist #TX-3737B
Member – American Society of Consulting Arborists
mattlathambcma@gmail.com
www.arboristondemand.org
