The oak tree is most commonly found in the Northern Hemisphere and has many deciduous and evergreen species. It is very popular, as a symbol of endurance. However, there are many diseases which affect this beautiful species, which we will discuss here.
Since the oak is considered to be a symbol of strength and longevity, it is hard to imagine a situation where this sturdy old giant can catch a flu. However, the diseases that affect them are often fatal.
Apart from these, attacks by insects such as forest tent caterpillars, gypsy moths, oak leaftiers, etc., are other challenges that this tree faces.
Anthracnose is a fungus-related ailment. These fungi feed on white oak and other shade trees. However, some of these fungi families only attack one tree, e.g., the white oak anthracnose will not attack any other tree except the white oak.
This fungus causes defoliation, killing, and girdling of buds and twigs, and premature loss of leaves. While this is not exactly fatal, repeated occurrences may cause stunted growth.
Oak tatters is a condition in which the leaves become lacy or tattered. It primarily affects the white oak group, while the occurrence is quite rare in other species. One of the symptoms is the lack of veins in the tree. This leads to faster regeneration of leaves, which stresses the tree. The healthy trees can survive, but the weaker ones succumb to it.
The oak wilt may be the most fatal disease. It is a fungal infection that affects the tree's vascular system, thus obstructing the flow of vital nutrients and water.
The symptoms are loss of color, early fall of leaves and, sometimes, appearance of a mat of fungus on the bark. Sadly, this condition cannot be cured. We can only save the other trees in the vicinity by killing the affected oak.
Powdery mildew is also a fungal condition that does not kill directly, but makes the tree susceptible by weakening its immune system. The first signs of mildew are yellow and green spots which eventually look as if the tree is covered with a veil of talcum powder. Powdery mildew can be cured with the help of fungicides.
The early symptom of this disease is sliminess on the bark. This sliminess attracts insects and green fungus that further the damage. The tree can be saved from wetwood only in the earliest stages, if the infected portion is cut. Otherwise, the tree will have to be cut down and burned to avoid the spread of wetwood to other trees.
Thus, we can see that some of the diseases can be cured, if detected early enough. So we have to keep an eye on our beloved oak to avoid occurrence and exacerbation of these diseases.