Sudden Oak Death: Causes and Treatments

Sudden Oak Death is a plant pathogen that kills oak and other species of trees. It has mostly affected trees located in California and Oregon as well as being somewhat present in Europe. According to information provided by suddenoakdeath.org,” Sudden Oak Death is a forest disease caused by Phytophthora Ramorum…These trees are infected through the trunk of the tree” (“What Is Sudden Oak Death?”. 2019.)  Phytophthora Ramorum is a plant pathogen. It’s located in areas that are cool, moist, and foggy. The pathogen was first discovered in the early 1990’s, being observed on container-growth plants located in nurseries. It was first isolated in 2000 from cankers on dying trees. Symptoms of the pathogen include bleeding cankers on the tree’s trunk and dieback of the foliage. Phytophthora Ramorum doesn’t produce spores or spread in dry conditions nor is it common in urban areas or suburban areas where native vegetation has been largely removed. If there is a tree that’s been infected with the pathogen then it would have already affected the surrounding area. If it’s a small infected area, then removal of the trees is recommended. To prevent the spread of the pathogen then it’s also recommended to stay out of wet areas that may be contaminated with it.

Phytophthora ramorum is the plant pathogen known to cause the disease called Sudden Oak Death, which currently doesn’t have a cure. This disease causes oak trees and other species of trees to die as the pathogen kills the tree from the inside of its trunk. P. ramorum was first recorded in 1995, and the pathogen’s origins are still uncertain, but most proof indicates that it was introduced as an exotic species on several occasions. The disease has very few control           mechanisms, and they depend on early identification and adequate disposal of infected plant material.

In the 1900’s when the disease was discovered, it was recognizable by a common trait that was being observed on a species of tree called Tanoaks. The disease can be acknowledged by wilting fresh roots, old leaves becoming pale green, and after two to three weeks, leaves turning brown as they cling to their branches. Dark brown sap can stain the bark of the reduced trunk. With noticeable discoloration, the bark can divide and exude the gum. Suckers attempt to sprout the next year after the tree comes back, but their tips quickly bend and die.

Get Help With Your Essay

If you need assistance with writing your essay, our professional essay writing service is here to help!
Find out more about our Essay Writing Service

P. Ramorum is still a new disease and the direct source of it is still uncertain. However, according to an article written by Matteo Garblotto and associates, “Our data shows that almost all of the main tree species in mixed-evergreen and redwood-tanoak forests of the state-including the coniferous timber species on the coast of redwood and Douglas fir- may be hosts of P. Ramorum.”. This claim is provided by data that the researchers received when examining the sampled leaves and stems of tree and shrubs species located within sites with oak mortality in California. Tests were also conducted on DNA of the plants. The DNA-diagnosis was made up of a process which included: 1) sample freezing, 2) grinding of infected plant tissue and extraction of DNA, and 3) amplification of P. ramorum DNA using the polymerase chain reaction. Overall the diagnosis was able to detect the pathogen within. 10 out of 13 of the sampled plants.

There is currently no cure for the Sudden Oak Death disease but there was an effective treatment that was able to put a stop to the disease for up to 2 years. Phosphonate treatments were effective in slowing infection and development rates for at least 18 months. By contrast, an alternative technique composed of azomite soil modification and bark lime wash was always ineffective and did not decrease growth rates or rates of infection. Matteo Garbelotto states, in an article about the many treatments of Sudden Oak Death,” these simple derivatives of phosphorous acid enhance the production of secondary metabolites that act as antibiotics” (Garbelotto et al. 2008).

In order to protect the trees against this devastating pathogen, checking the trees for the noticeable symptoms is necessary. There are two main sections of the tree that pathogen can use as a host. Those two main sections are the trunk and the foliar. The trunk infection is used to kill the tree more quickly. The foliage infection can range from leaf spots to twig dieback. These hosts,however, rarely die from the infection. Examining plants from these symptoms and administering any treatments is the only to prevent the spread of this pathogen to new plants. If one were to use insecticides as a form of treatment then it wouldn’t have any result when in comparison to phosphonate treatments. The only effect the insecticide can have is prolonging th tree’s lifespan for a minimum time but only if it’s applied when the disease is not an advanced stage.

Sudden Oak Disease may be a new plant pathogen but at least there are temporary treatments to keep it at bay instead of there being no help at all. There are also many ways to prevent the spread of the pathogen and what to do to contain it.

References

• Garbelotto, Matteo, and Douglas Schmidt. “Phosphonate Controls Sudden Oak Death Pathogen for up to 2 Years.” California Agriculture, University of California, Agriculture and Natural Resources, 1 Jan. 2009, calag.ucanr.edu/Archive/?article=ca. v063n01p10.
• Garbelotto, Matteo, et al. “Non-Oak Native Plants Are Main Hosts for Sudden Oak Death Pathogen in California.” California Agriculture, University of California, Agriculture and Natural Resources, 1 Jan. 2003, calag.ucanr.edu/Archive/?article=ca. v057n01p18.
• “What Is Sudden Oak Death?” Sudden Oak Death, 2 Sept. 2017, www.suddenoakdeath.org/about-sudden-oak-death/.