What Is Botrytis: Why Is It Killing My Redwoods?

What is Botrytis?

Botrytis, also known as gray mold, is a fungal disease that occurs virtually everywhere. It can affect over 300 different plant species and has a wide range of hosts, including soft fruit such as strawberries, tomatoes, grapes, and, yes, trees.

The fungus Botrytis Cinerea or gray mold is a serious plant pathogenic disease. Gray mold can be devastating to plants because it survives through overwintering in soil or on infected plant debris, allowing it to maintain a presence in your yard year after year.

Here’s more valuable information about Botrytis and what to do about it from a professional tree removal service in Sacramento.

What Is Botrytis? Common Signs and Symptoms in Redwood Trees

Botrytis cinerea is the causal fungus for Botrytis blight of redwood trees.

The fungus is a pathogen that thrives in cool, wet environmental conditions and causes leaf drop and branch dieback in infected redwood trees. Besides leaf drop, symptoms include gray mold on dead tissue and brown spots on foliage.

In severe cases, Botrytis blight can kill off entire branches and possibly even kill the tree.

Signs and symptoms of Botrytis Cinerea on Redwood trees include:

  • Needles with purple, oval, or circular or oval spots that expand to cover the entire needle.
  • The needle eventually turns brown
  • Any spotting may concentrate on lower branches.
  • Purplish brown spots at the base of the needle, which become cankers that eventually girdle the twig.
  • Tiny black stromata containing pycnidia or perithecia in discolored areas.

How Do You Manage Botrytis in Redwood Trees?

Although you cannot cure redwoods with Botrytis blight, you can manage it with some steps to help save your tree’s life.

Avoid Over-Wetting the Foliage

Avoid wetting foliage directly with irrigation water by using drip or micro-sprinkler irrigation methods instead of overhead sprinklers to irrigate your redwood tree.

Improve Air Circulation between Trees

Improve air circulation around plants to dry out moisture quickly after rainstorms or irrigation events. For example, space plants out when planting them to allow adequate room between them for air to flow freely around the plant leaves and branches.

Prune Your Trees Regularly

Prune regularly to remove crowded overhead foliage and branches and improve air circulation between trees.

Remove Infected Leaves, Branches, or Trees

If Botrytis has infected your redwood tree, remove all infected leaves and branches from the tree, or, in severe cases, fell the tree altogether.

Apply Preventative Fungicides

Prevention is always the best medicine, and this is true when it comes to gray mold in your Redwood trees.

If you’re trying to prevent gray mold from developing on your trees, apply the fungicides chlorothalonil, thiophanate methyl, or triforine before any disease develops.

Contact a Professional Arborist in Sacramento to Help Manage the Health of Your Trees

We hope we’ve adequately answered your question, “What is Botrytis?”

At Fallen Leaf Tree Management, we’re all about making sure our customers get the most out of their trees. From planting to removal, you want to know that your trees are in good hands.

For example, we offer various tree health services that can help you avoid Botrytis, including tree pruning and trimming, crown reduction, and tree removal.

When it comes to your trees, you want to make sure that you’re working with an arborist that can offer a complete range of services so that you don’t have to shop around.

Our ISA-certified and qualified tree technicians can help you learn more about plant health care and have years of experience to give your trees and shrubs the best care possible.

Call 916-447-8733 or contact us today to schedule a free estimate and on-site assessment in Sacramento, CA. 

Fallen Leaf Tree Management

Expert Tree Care in the heart of Sacramento & surrounding areas with your satisfaction guaranteed. One of our Arborists can give you a comprehensive evaluation on all the trees and shrubs in your landscape and give you a scheduled maintenance plan. Call for an arborist consultation.



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