Symptoms
The fungus enters through wounds and grows in and beneath the bark, eventually killing the cambium all the way round the twig, branch or trunk. The first symptom of C. parasitica infection is a small orange-brown area on the tree bark. A sunken canker then forms as the mycelial fan spreads under the bark. As the hyphae spread, they produce several toxic compounds, the most notable of which is oxalic acid. This acid lowers the pH of the infected tissue from around the normal 5.5 to approximately 2.8, which is toxic to plant cells. The canker eventually girdles the tree, killing everything above it. Distinctive yellow tendrils (cirrhi) of conidia can be seen extruding from the stroma in wet weather.
Read more about this topic: Chestnut Blight
Famous quotes containing the word symptoms:
“Protest, evasion, merry distrust, and a delight in mockery are symptoms of health: everything unconditional belongs in pathology.”
—Friedrich Nietzsche (1844–1900)
“The human condition is such that pain and effort are not just symptoms which can be removed without changing life itself; they are the modes in which life itself, together with the necessity to which it is bound, makes itself felt. For mortals, the “easy life of the gods” would be a lifeless life.”
—Hannah Arendt (1906–1975)
“Murderous desire, hatred, distrust are nowadays the accompanying signs of physical illness: so thoroughly have we embodied our moral prejudices.—Perhaps cowardice and pity appear as symptoms of illness in savage ages. Perhaps even virtues might be symptoms.”
—Friedrich Nietzsche (1844–1900)