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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 ]
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.
Download as PDF; Printable version; ... Hypoxylon canker of shade trees; L. List of elm diseases; List of pistachio diseases;
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 ...
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.
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.
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.
Most trees affected by AOD will display exit holes and galleries caused by the larvae of the two-spotted oak borer Agrilus biguttatus [7]. Larvea of A. biguttatus and the bacterial pathogens are acting together in causing the disease, with the bacteria being more virulent and causing larger lesions when trees are infected with beetle larvae. [ 8 ]