The cherry tree, native to most of Europe, has a long history of cultivation. The ancient Greeks grew cherry trees 2,300 years ago. The Romans also valued the cherry tree, taking them to Britain in the first century. Modern gardeners cultivate three types of trees: sweet cherry, sour cherry and sweet-sour trees, also called dukes. A variety of diseases can strike any of these types; inspect cherry tree leaves, blossoms and fruit to identify the culprit and treat accordingly.
Look for blossoms that turn brown and light brown circles on green fruit. These symptoms indicate brown rot, a serious fungal disease that can destroy a cherry tree's mature fruit. The rotted fruit often remains on the tree.
Check for small spots on the leaves that start out yellow and then turn brown. Also watch for entire leaves that turn yellow and drop prematurely. These signs indicate that cherry leaf spot disease, which is caused by a fungus, has struck your tree. The tree might drop all of its leaves if the outbreak is severe. Rake and destroy any fallen leaves, since the fungus survives in the leaf litter.
Examine the leaves for a powdery white substance that might have small black spots. This signals that your tree has powdery mildew, another fungal disease. Powdery mildew does not require control in many cases; for severe outbreaks, apply a fungicide.
Check for cankers, areas of diseased or dead tissue, that ooze an amber gummy substance. This indicates the presence of bacterial canker disease, which can kill the tree. The best control method requires applying an antibiotic, such as streptomycin, according to the Virginia Cooperative Extension.
Avoid using a high-nitrogen fertiliser in the vicinity of cherry trees. This can increase their susceptibility to brown rot, according to the Washington State University Extension.