155 Chestnut Blight Facts: Symptoms, Treatment, And Prevention

Chestnuts are nuts of deciduous trees and are used as substitutes for potatoes in many countries.

The chestnut, a native of the northern hemisphere, can grow either in bush or tree form. Chestnut blight fungus is a fungal bark disease with the scientific name Cryphonectria parasitica.

As per research, it is believed that there are billions of chestnut trees around the Florida and Mississippi areas. They give edible nuts which are used in day-to-day American culture. Chestnut trees once existed widely but now it is very rare to find American chestnut trees in their native range. There are only 430 million American chestnut trees found in their native range.

There are a lot of facts about the chestnut blight fungus that you should know so keep reading and enlighten yourself with facts about chestnuts.

Let's explore some facts about the chestnut tree species and the causes of chestnut blight fungus. If you want a similar read please check out Bulrush plant facts and algae for kids.

Facts About Chestnut Blight

This blight fungus changed the entire situation for Eastern forests and became a threat to the chestnut species across North America. This tree disease shattered the growth of most young native chestnut trees in US forests.

Sunlight is the best companion of these edible trees, and they exhibit remarkable growth in sunny environments. Loamy soil is best suitable for its growth and wetlands are not favorable.

These trees are loved because of their sweet nuts which can be roasted. These nuts are used in soups and salads. The wood of these trees also was a part of native American citizens' culture. People in the past were highly dependent on these trees. There was a saying that Americans' lives passed in the company of chestnut trees which were used to make things from baby cribs to coffins. This illustrates the dependency native Americans had on these huge trees.

Mature trees can grow up to 100 ft (30.48 m) in height and produce as many as 40,000 nuts. They are branch-free trees that grow extremely straight, and the trunk reaches almost 14 ft (4.27 m) in diameter. The wood is very durable, strong, and rot-resistant. The inner part of the wood is mostly brownish and eventually changes to reddish color with time. Its wood doesn't shrink and decay easily like other wood. You can still see some houses and furniture built with chestnut wood in some areas of North America. Chestnuts used to be one of the important sources for livestock survival.

There are many chestnut trees; among them, American chestnut trees are of fine quality. Other chestnut varieties include dwarf chestnut trees (Castanea pumila), Chinese chestnut trees, and Japanese chestnut trees. The quality of Asian chestnut trees cannot compete with the quality of Native American chestnut trees. As per the American Chestnut Foundation, the American chestnut tree is going extinct because of a dreadful fungus. As per IUCN, the American chestnut is considered endangered in USA and Canada. Some of these trees are still found in the north Michigan range as they might be blight resistant. As this blight disease damages the bark system, the blight can be more visible on the bark of these trees. However, the root system can still survive and emerge as a young sprout. Young trees grow up to 15 ft (4.57 m) tall and they can produce nuts before being again affected by blight disease. These nuts help in the regrowth of a new generation of chestnut trees.

The first tree affected with chestnut blight was found in the New York Botanical Garden. The chestnut blight was especially prevalent by 1910, especially on American chestnut trees. Farmers started to entirely burn down any blight-affected chestnut tree so that the blight would not spread to other trees. The parasite spread in its native range and affected trees outside its range. Despite farmers and scientists struggles, they could not control the spread of this plant disease and it spread like wildfire.

All this happened because of the fungus named Cryphonectria parasitica, native to Asian countries. This fungus spreads quickly and damages the entire forest. Let's explore the symptoms, causes, and treatments for this contagious fungal disease in other sections of the article.

Causes Of Chestnut Blight

American chestnuts are considered the queen of eastern American forest trees, the finest chestnut tree globally, and redwoods of the east as they are an important and large range of trees found in the North American area. Chestnuts are a good source of fiber, vitamins and minerals. If chestnut blight was not such a huge problem, the chestnut might become the national nut of America. Let's learn about the main causes of chestnut blight disease.

The main causal agent of chestnut blight disease is the Cryphonectria parasitica fungus. In 1904, the USA first introduced Japanese chestnut trees for trading and cultivation purposes. A Cryphonectria parasitic from eastern Asia entered North America during this period, called the chestnut blight fungus. Though the same blight infection is found in European chestnut trees, it did not create as much devastation in these areas because of the growth of CHV1, which is a threat for the C. parasitica fungus. Despite the fact that chestnut blight evolved from an Asian species, the Japanese chestnut and Chinese chestnut trees are both resistant to this fungus and have become blight resistant. European chestnuts are moderately affected by this disease. Other trees such as oak, shagbark, hickories, and maples are also attacked and devasted by this dreadful fungus.

Treatment And Prevention Of Chestnut Blight

This chestnut blight fungus is an invasive species and has adverse effects on humans, wild animals, and the entire ecosystem. Chestnuts are important food sources for animals like chipmunks, deer, squirrels, and wood ducks. Humans have faced huge financial losses because of the blight disease, and the lumber and nut industries faced a huge crisis. Let's find out if we can treat and prevent this fungus disease.

In the past, one method to treat the blight disease was using mudpacks. W.H. Weidlich is behind this idea. The ingredients required to make a mudpack are pure soil free from pesticides and fertilizers (preferably compost), a plastic cover or bag, and string to tie the cover. First, prepare a sticky and thick soil by adding some water to the soil and then apply this pack on the bark of the blight-affected trees, cover the bark with plastic to retain moisture, and tie with strings. Leave the cover on the tree for at least two months and then remove the cover. By this time, the blight fungus should be almost dead. Unfortunately, this method is not favorable for large groups of trees. Another disadvantage of this method is though it treats the blight-affected area, the fungus may attack other parts of the plant in the meantime.

Though it is impossible to change history and recreate the strong, widespread, huge species of chestnut trees, the USDA started a program to safeguard these trees from this fungus disease. It is impossible to eradicate the fungal disease from American forests; the only way is to develop and modify the tree's resistance to deal with the fungus. Several types of research are being carried to restore, conserve and bring back the glory of chestnut fairytales. As we know, both Japanese and Chinese chestnuts are moderately blight-resistant trees, so researchers have focused on crossing American chestnut trees with the Chinese chestnut. The main aim is to create blight-resistant chestnut trees with American chestnut species features.

Further, the offspring of these crossbreeds are bred back with American chestnut trees. The idea is to create genetically pure American chestnut species that are blight-free. The first crossbred American chestnut tree that survived the blight disease is the clapper.

Another beneficial method implemented is genetic engineering. In 1990, the State University of New York adopted a completely new method for generating blight resistance chestnut trees. With this method, scientists started to introduce a disease resistance gene into the DNA of the tree. Genetic engineering research started creating a symbiotic relationship between the chestnut tree and blight fungus to coexist without disturbing each other's growth. In this system, a gene found in the wheat plant is fungal resistant, so scientists introduced these genes into the DNA of the tree. In 2006, the first genetically improvised trees were planted as a trial. This research proved to be extremely beneficial. The newly engineered American chestnut trees show a similar blight resistance to Chinese chestnut trees. Though some criticize this practice, genetic engineering is the safest method to adopt and has maximum chances to bring back the lost glory of chestnut trees.

Symptoms Of Chestnut Blight

The toxic fungus is named blight fungus because it attacks the bark and spreads quickly to branches and stems, eventually making these huge, historic trees die. This disease circulates throughout the entire tree, and it can eat away at the whole tree, except its roots, in no time. Chestnut blight is one of the greatest tragedies in American forest history.

How can you identify if a chestnut tree is affected by this disease? This fungal disease enters into wounds (made by small insects or worms) or bark cracks and starts developing below the bark. This disease mainly targets the vascular cambium of the tree. What is vascular cambium? It is a tissue present in the stem and root part that supplies essential nutrients and water to the entire tree. From there, the real destruction of the plant starts. The affected bark area turns reddish-brown or sometimes yellowish-brown. The leaves of the affected branch change color to brown. As the fungus spores develop, they start controlling the plant by forming cankers. These cankers prevent trees from getting water in all of its parts, forcing the tree to die because of lack of moisture. The same spores can spread to other neighboring trees through various carriers. But there is a small ray of hope: the root systems are not completely damaged, so there are chances of regrowth of small sprouts, and if they have little blight resistance, they may grow to minimum height, and hopefully, can start producing nuts. However, these new shoots may have less chance of survival from this tree disease.

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