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The most obvious symptom of this disease is the yellowing of leaves before they drop in the early spring. Infected leaves are filled with numerous black lesions that cover an obvious portion of the leaf. [5] These lesions first appear as small purple spots which turn red to brown and then black.
Weeping Higan Cherry trees are rather prone to problems, particularly in dry soil. A type of bacterium can cause leaf spots and twig cankers. Small, reddish spots dry and drop out. A fungus can cause reddish spots which drop out leaving shot holes. Once the holes appear the leaves may fall from the tree and the disease is worse in wet weather.
Hypholoma fasciculare grows prolifically on the dead wood of both deciduous and coniferous trees. It is more commonly found on decaying deciduous wood due to the lower lignin content of this wood relative to coniferous wood. Hypholoma fasciculare is widespread and abundant in northern Europe and North America.
The tiny insect larva is attacking black locust trees.
Shot hole disease is a major concern of the stone fruit industry. It is estimated that 80% of the California almond crop may be infested with shot hole disease, resulting in a potential yield loss of 50-75%. [3] In the 1930s, it was found that applications of Bordeaux mixture reduces shot hole disease on peaches from 80% to 9%.
Spalting is divided into three main types: pigmentation, white rot, and zone lines.Spalted wood may exhibit one or all of these types in varying degrees. Both hardwoods and softwoods can spalt, but zone lines and white rot are more commonly found on hardwoods due to enzymatic differences in white rotting fungi.
“In some places, trees with nests of rare or endangered species are marked,” says Christopher Evans, extension forestry and research specialist at the University of Illinois Urbana-Champaign.
Rhytisma acerinum is a plant pathogen that commonly affects sycamores and maples in late summer and autumn, causing tar spot. Tar spot does not usually have an adverse effect on the trees' long-term health. [1] R. acerinum is an Ascomycete fungus that locally infects the leaves of trees and is a biotrophic parasite. [2]