Sphaeropsis tumefaciens

Sphaeropsis tumefaciens is a fungal pathogen that causes disease in various plant species. It is known for causing Sphaeropsis gall or Sphaeropsis knot, a disease characterized by the formation of large, woody galls on the branches and trunks of infected trees.

Taxonomy

Sphaeropsis tumefaciens belongs to the Ascomycota division of fungi, specifically within the Diplodia genus. It was previously known as Diplodia tumefaciens, but was reclassified due to differences in its sexual reproduction and spore morphology.

Hosts and Symptoms

Sphaeropsis tumefaciens affects a wide range of hardwood and conifer species, including pines, spruces, and firs. Symptoms of infection include the formation of large, woody galls on the branches and trunks of trees. These galls can cause significant damage to the tree, often leading to branch dieback and, in severe cases, tree death.

Disease Cycle

The disease cycle of Sphaeropsis tumefaciens begins when spores are released from mature galls and spread to new hosts via wind or rain. The fungus then penetrates the host's tissue, causing the formation of a gall. The gall continues to grow as the fungus reproduces, eventually releasing more spores to infect new hosts.

Management

Management of Sphaeropsis gall involves a combination of cultural practices and chemical control. Infected branches should be pruned and destroyed to prevent the spread of the fungus. Fungicides can also be applied to protect susceptible trees during periods of high disease pressure.

See Also

• Diplodia
• Ascomycota
• Gall