Menu
Spraying Spruce Trees

Rhizosphaera Needle Cast

, ,

Rhizosphaera Needle Cast

Rhizosphaera needle cast, caused by the fungus Rhizosphaera kalkhoffii, is a fungal disease that affects spruce trees, causing needles to turn brown or purplish-brown and fall off. The disease often starts on the lower branches and progresses upward, and from the inside of the tree outwards. Spraying with fungicides can be an effective way to help trees, especially in preventing and managing fungal diseases. Fungicides work best as protectants, meaning they are most effective when applied before a tree is exposed to a pathogen. While they can’t reverse damage already done by fungal infections, they can help prevent the spread of disease and potentially put existing infections into remission. 

 
To spray spruce trees for needle cast, the general recommendation is to apply fungicides when the new needles are half-elongated, typically in late spring or early summer.A second application should be made 3-4 weeks later, often when the needles are fully elongated. For Rhizosphaera needle cast, multiple applications may be needed, with a second application 3-4 weeks after the first and possibly a third after that. 
Elaboration:
  • Timing is crucial:

    Applying fungicides at the correct time is essential for effectiveness, as it prevents the fungus from becoming established on the new needles. 

     
  • First application:

    The first application is typically done when the new needles are about half-elongated, usually in late spring or early summer. 

     
  • Second application:

    A second application is recommended 3-4 weeks after the first, ensuring protection for the developing needles. 

     
  • Multiple applications:

    For certain types of needle cast, like Rhizosphaera, a minimum of 3 applications may be needed, spaced 3-4 weeks apart, to effectively control the disease. 

     
  • Types of fungicides:

    Fungicides containing chlorothalonil or copper are often used for Rhizosphaera needle cast. 

     
  • Prevention:
    Good air circulation, spacing trees, and proper mulching can help prevent needle cast.
     
    Reach out to us at Johnson Ops Tree Care for a tree evaluation; together, we can create a plan to ensure your trees stay healthy. 608 526-6297
     

Related Posts