Brown Leaves on Redwoods

Redwoods are susceptible to a fungal infection.

Redwood trees (Sequoia sempervirens) are evergreen conifers that grow 70 to 90 feet tall. Redwoods have a rapid growth rate and are often planted in groves. The trees adapt well to a variety of climates and thrive in full sun. A fungal disease causes brown redwood foliage.

Identification

Redwoods are susceptible to the fungal disease botrytis blight caused by Botrytis cinerea. The fungal growth is more rapid in areas of high humidity and during cool spring and fall weather. The fungus affects all above-ground plant parts.

Damage

The disease is characterized by browning and drooping foliage. Affected leaves are stunted in growth and start to decay. As disease progresses, there are gray brown masses of spores on affected areas accompanied by twig dieback. The fungal spores overwinter in the twigs and debris under trees.

Management

Prune and remove all affected tree areas and thin the canopy as this allows light and air inside the tree. Keep tree clear of fallen foliage, weeds and debris. Do not use overhead irrigation methods as this promotes moisture in the tree. Chemical control options include chlorothalonil, neem oil or Bacillus subtilis.

References

• University of California Extension: Redwood
• University of California Extension: Botrytis Blight
• Cornell University Extension: Botrytis Blight