Fungus & Lichens on Fruit Trees

Basics

• Lichens are actually two organisms in one body. They are a combination of a specialized fungus and a specialized type of algae in a symbiotic relationship. Lichens appear as colonies of white or other colored, flaky material over dead or dying tree limbs, especially during the winter months or on branches not receiving sunlight. They are not particular about what kind of trees they attach and may be found on various fruit trees, like apple trees or pear trees.

Symbiosis

• Fungi cannot produce their own food and must derive nutrients from other organisms. This is known as parasitism. In lichens, the specialized fungi bond with algae, which are capable of photosynthesizing sunlight into energy, which is then shared with the host fungus. Lichens may also use a special type of bacteria known as cyanobacteria instead of algae.

Appearance on Trees

• Lichens appear only on the parts of trees that are not healthy or open to sunlight. They are extremely adaptable organisms that survive in conditions other organisms may find unfavorable, and thus take up niches that would otherwise be empty. The lichens do not cause the death of an organism and are not harmful to fruit tree.

Other Locations

• Lichens do not exclusively grow on trees. They grow almost wherever there is very little life or organic material. They may be found on rocks, fallen logs, dead trees or even on ground cover. There is almost no limit to where the organisms grow because of their extreme ability to subsist on very little sustenance.