“Dutch elm disease is a fungal disease that literally strangles elm trees by invading the tree,” (Burke 429). It is caused by ascomycete, Ceratocystis ulmi and spread from tree to tree by the aid of beetles. During its growth, Dutch elm tree produces hyphae from its mycelium that spread throughout its parts. The spreading of the produced hyphae enhances the tree to produce plugs that play a significant role in cutting off the xylem vessels which are responsible for movement of water within the plant. “The cutting of the xylem leads to branch wilt and eventually the death of the whole tree,” (Burke 429).
Dutch elm disease did not originate from Netherland as its name may suggest. Its name originated from a female Dutch scientist who discovered it in early 1920’s. It has no scientific name, and thus, it is known as Dutch elm disease worldwide.
Symptoms of Dutch elm disease
The symptoms of Dutch elm disease are evident both externally and internally. During its early stages, it causes premature yellowing of the leaves that are near the crown. Its early symptoms are also associated with sudden or prolonged wilting of plant leaves, branches or sometimes the entire plant. “The wilted leaves of the plant affected by this disease appear not only curled, but also yellow,” (Agrios 273). The advancement of the disease makes the leaves turn brown, and eventually fall off from the tree prematurely. Most branches of the plants infected by this disease die instantaneously after defoliation. The disease spreads very first from one branch to another. Thus, a severely affected plant poses many dead branches. In some occasions, the disease leads to the death of the whole plant after affecting almost all of its parts. Usually, it infects elm trees during spring or early summer. However, those infected in late summer do not develop the symptoms so much; in most occasions they recover. Dutch elm disease also causes sapwood discoloration (Agrios 273).
Plants affected by Dutch elm disease and immune species
Dutch elm disease is one of the major pathogenic diseases in America. It affects almost all elm trees. However, it is evident that some species of elm are affected more than the others by this disease. “In America, this disease is caused by two types of fungi; Ophiostoma novo-ulmi and Ophiostoma ulmi,” (Agrios 279). Some species of American elm are also resistant to this disease. For instance, “Asiatic species such as the Siberian and the Chinese elm are resistant to it,” (Agrios 279).
Dutch elm disease not curable
Dutch elm disease is not curable; there are no remedies for it after it affects trees. However, early identification of the problem and application of appropriate treatments may aid minimize the loss of elm trees. Its incidence can be reduced by removal of some parts. For instance, removal and immediate demolishing of all the affected parts has proved effective; peeling the bark off aid in eradicating the beetles that transmit this disease. “Mechanical destruction of root grafts and injection of the appropriate dosage of registered fungicides also aid significantly in managing this disease,” (Allison et al 2).
Prevention of Dutch elm disease
Hybrid between different plants species have been found effective in controlling the occurrence of this disease. In most occasions, plant crossing result to hybrid plants that portray some degree of resistance to the disease. Seedling selection is also influential. For instance, Christine Buirman elm, a product of seedling selection, has performed successively in some areas. Currently, it is among the seeds that are planted extensively in diverse areas that used to be inhabited by the disease causing organisms.
Prevention of this disease also involves observance of sanitation. Observation of sanitation involves eradicating the breeding zones of the organisms that cause this disease. For instance, removal and destruction of dead elms aid significantly in denying the larvae of the insects and the fungus a reproducing environment. Pruning out of the infected branches and twigs is also effective; it contributes to the elimination of this disease. It is also crucial for the farmers to spray their elm trees with chemicals such as methoxychlor when still healthy; this aid significantly in keeping away the potential careers and causing agents of Dutch elm disease. Currently, there is great use of insecticide in America. The insecticide such as Bidrin regulates the existence of bark beetles that play the role spreading the disease from tree to tree by direct killing. Some farmers also employ Vapam drenches in their farms. Use of Vapam drenches between elm tree roots aids in not only killing the roots, but also preventing formation of root grafts between adjacent trees. “The killing and separation of roots prevents further spreading of the disease via root grafts,” (Agrios 280).
Conclusion
In conclusion, Dutch elm disease is a fungal infection of elm trees. Its effects are so fatal to plants. It is one of the common elm diseases in Northern Europe and United States of America. It is spread from tree to tree by the elm beetles. Its control involves eradication of the career beetles, removal of the affected plants, pruning, and use of Vapam drenches.
Works Cited
Agrios, George. Plant Pathology. New York: Elsevier, 2012. Print
Allison, James et al. How to save Dutch elm diseased trees by pruning. New York: Dept. of Agriculture, Forest Service, Northeastern Area, State and Private Forestry, 1979. Print.
Burke, Don. The Complete Burke’s Backyard: The Ultimate Book of Fact Sheets. New York: Murdoch Books, 2005. Print.