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Beech bark disease is a disease that causes mortality and defects in beech trees in the eastern United States, Canada and Europe. [ 1 ] [ 2 ] [ 3 ] In North America , the disease occurs after extensive bark invasion by Xylococculus betulae and the beech scale insect , Cryptococcus fagisuga . [ 4 ]
Aleurodiscus oakesii on tree bark. Aleurodiscus oakesii is the most common fungi to cause “smooth patch disease” on the nonliving outer bark of trees. This fungal infection can lead to trees shedding and leaving smooth and lighter patches of bark on the tree, giving “smooth patch” its meaning.
Pinus torreyana is a broad, open-crowned pine tree growing to 8–17 meters (26–56 ft) tall in the wild, with 25–30 centimeters (9.8–11.8 in) long leaves ('needles') in groups of five. The cones are stout and heavy, typically 8–15 cm (3.1–5.9 in) long and broad, and contain large, hard-shelled, but edible, pine nuts . [ 4 ]
Trees have natural chemicals that keep most fungi at bay, but climate change could be making trees more vulnerable, researcher says. Citizen scientists to study this tree disease found in ...
Dutch elm disease was spread by elm bark beetles, yet the tree mortality was caused by a pathogen. [4] Chestnut blight is a fungus spread through wind dispersal and rain splatter; the blight traveled up to 50 miles in a year by natural means. [5] Insect pests, once they reach the adult phase, have the ability to disperse by flight.
It is caused by phytoplasmas which infect the phloem (inner bark) of the tree. [2] Similar phytoplasmas, also known confusingly as 'Elm yellows', also occur in Europe. [3] Infection and death of the phloem effectively girdles the tree and stops the flow of water and nutrients. The disease affects both wild-growing and cultivated trees.
Where beech bark disease becomes established, most of the larger trees will die. Some trees seem to be partially resistant to the disease and a small number seem to be completely resistant. This may be partly due to the fact that trees with smooth bark provide fewer cracks and crevices in which the scale insect can flourish. [8] [9]
As the tree declines, more bark beetles are attracted and more cankers are formed. Eventually the enormous number of beetle attacks and subsequent canker formation overwhelms and kills the tree. Thousand cankers is a progressive disease and its effects result from the culmination of a large number of relatively small cankers over a period of time.