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The Douglas fir is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three varieties: coast Douglas-fir, Rocky Mountain Douglas-fir and Mexican Douglas-fir.
Botrytis cinerea is a necrotrophic fungus that affects many plant species, although its most notable hosts may be wine grapes. In viticulture, it is commonly known as "botrytis bunch rot"; in horticulture, it is usually called "grey mould" or "gray mold".
Alnus rubra, the red alder, is a deciduous broadleaf tree native to western North America.
Thuja plicata is an evergreen coniferous tree in the cypress family Cupressaceae, native to western North America. Its common name is western redcedar, and it is also called Pacific redcedar, giant arborvitae, western arborvitae, just cedar, giant cedar, or shinglewood. It is not a true cedar of the genus Cedrus.
A leaf spot is a limited, discoloured, diseased area of a leaf that is caused by fungal, bacterial or viral plant diseases, or by injuries from nematodes, insects, environmental factors, toxicity or herbicides. These discoloured spots or lesions often have a centre of necrosis. Symptoms can overlap across causal agents, however differing signs and symptoms of certain pathogens can lead to the diagnosis of the type of leaf spot disease. Prolonged wet and humid conditions promote leaf spot disease and most pathogens are spread by wind, splashing rain or irrigation that carry the disease to other leaves.
Phytophthora cambivora is a plant pathogen that causes ink disease in European chestnut trees. Ink disease, also caused by Phytophthora cinnamomi, is thought to have been present in Europe since the 18th century, and causes chestnut trees to wilt and die; major epidemics occurred during the 19th and 20th centuries. P. cinnamomi and P. cambivora are now present throughout Europe since the 1990s. Ink disease has resurged, often causing high mortality of trees, particularly in Portugal, Italy, and France. It has also been isolated from a number of different species since the 1990s, including:
Durandiella pseudotsugae is a plant pathogen which causes Dime canker in Douglas-fir trees.
Melampsora medusae is a fungal pathogen, causing a disease of woody plants. The infected trees' leaves turn yellowish-orange. The disease affects mostly conifers, e.g. the Douglas-fir, western larch, tamarack, ponderosa, and lodgepole pine trees, but also some broadleaves, e.g. trembling aspen and poplars. Coniferous hosts are affected in late spring through early August, and trembling aspens and poplars from early summer to late fall. It is one of only two foliage rusts that occur naturally in British Columbia.
Stereum sanguinolentum is a species of fungus in the Stereaceae family. A plant pathogen, it causes red heart rot, a red discoloration on conifers, particularly spruces or Douglas-firs. Fruit bodies are produced on dead wood, or sometimes on dead branches of living trees. They are a thin leathery crust of the wood surface. Fresh fruit bodies will bleed a red-colored juice if injured, reflected in the common names bleeding Stereum or the bleeding conifer parchment. It can be the host of the parasitic jelly fungus Tremella encephala.
Rhabdocline pseudotsugae is a fungal plant pathogen. The pathogen, along with Rhabdocline weirii causes Rhabdocline needlecast; R. weirii only affects Douglas-fir trees. The disease causes the needles of the tree to discolor and eventually fall from the tree. It was originally common to the Rocky Mountain states of the United States but has since spread to Europe. Infections usually start in the spring or early summer and can change the color of the foliage to a variety of hues. The fungus produces apothecia that are normally found on the underside of needles but they also occur on the topside as well.
Phellinus pini is a fungal plant pathogen that causes tree disease commonly known as "red ring rot" or "white speck". This disease, extremely common in the conifers of North America, decays tree trunks, rendering them useless for lumber. It is a rot of the heartwood. Signs of the fungus include shelf-shaped conks protruding from the trunks of trees. Spores produced on these conks are blown by the wind and go on to infect other trees. Formal management of this disease is limited, and the disease is controlled primarily by cultural practices. Red ring rot is an important forest disturbance agent and plays a key role in habitat formation for several forest animals.
Phellinus weirii is a plant pathogen causing laminated root rot in certain conifers, typically Douglas-fir and western redcedar. It is widespread in the Douglas-fir growing regions of British Columbia, Washington and Oregon.
Christmas tree cultivation is an agricultural, forestry, and horticultural occupation which involves growing pine, spruce, and fir trees specifically for use as Christmas trees.
Pine and fir trees, grown purposely for use as Christmas trees, are vulnerable to a wide variety of pests, weeds and diseases. Many of the conifer species cultivated face infestations and death from such pests as the balsam woolly adelgid and other adelgids. Aphids are another common insect pest. Christmas trees are also vulnerable to fungal pathogens and their resultant illnesses such as root rot, and, in the U.S. state of California, sudden oak death. Douglas-fir trees in particular are vulnerable to infections from plant pathogens such as R. pseudotsugae.
Laminated root rot also known as yellow ring rot is caused by the fungal pathogen Phellinus weirii. Laminated root rot is one of the most damaging root disease amongst conifers in northwestern America and true firs, Douglas fir, Mountain hemlock, and Western hemlock are highly susceptible to infection with P. weirii. A few species of plants such as Western white pine and Lodgepole pine are tolerant to the pathogen while Ponderosa pine is resistant to it. Only hardwoods are known to be immune to the pathogen.
Lophodermium is a genus of fungi within the family Rhytismataceae. The genus contains 145 species and has a global distribution. Species of this genus are usually observed producing zone lines, conidiomata and ascomata on dead fallen leaves, but at least some are known to colonize living leaves. In many cases they then live inside the colonized leaf as a symptomless endobiont, where they are regarded as detritivores utilising dead plant matter. In a few cases they may kill all or part of the leaf prematurely, and there is a substantial literature dealing with those species as plant pathogens. The genus infects many different plant families but with a notable concentration in the family Pinaceae; many Lophodermium species are restricted to a single host genus, but some, particularly those infecting grasses, may infect several genera. Some are economically important plant pathogens, such as those that cause needlecast disease in European Black Pine, Scots Pine and Red Pine in forestry and christmas tree plantations. In these species, notably L. pinastri and L. seditiosum, the fungal spores disperse and infect the pine needles in late summer, which turn brown by the following spring and then fall off.
Forest pathology is the research of both biotic and abiotic maladies affecting the health of a forest ecosystem, primarily fungal pathogens and their insect vectors. It is a subfield of forestry and plant pathology.
Fusarium circinatum is a fungal plant pathogen that causes the serious disease pitch canker on pine trees and Douglas firs. The most common hosts of the pathogen include slash pine, loblolly pine, Monterey pine, Mexican weeping pine, and Douglas fir. Like other Fusarium species in the phylum Ascomycota, it is the asexual reproductive state of the fungus and has a teleomorph, Gibberella circinata.
Chrysomyxa weirii, is a fungus that causes a disease, commonly known as Weir's cushion rust, of spruce trees. It is mostly a cosmetic problem, causing yellowish spotting and banding on spruce needles, but in some cases can cause severe premature defoliation. Weir’s cushion rust can also disfigure and reduce growth of spruce trees by targeting the tender needles of newly emerging shoots. This pathogen's spores are spread by wind and water splash and germinate to infect newly developing needles on the same spruce, or neighboring spruce trees. Unlike many other rust disease pathogens, C. weirii is autoecious, only infecting spruce trees. C. weirii is also microcyclic, producing only two of the five possible spore stages common in rust fungi. Trees affected by Weir's cushion rust usually have obvious symptoms, but if treated correctly, the disease can be managed.
Plants and fungi communicate via mycorrhizal networks with other plants or fungi of the same or different species. Mycorrhizal networks allow for the transfers of signals and cues between plants which influence the behavior of the connected plants by inducing morphological or physiological changes. The chemical substances which act as these signals and cues are referred to as infochemicals. These can be allelochemicals, defensive chemicals or nutrients. Allelochemicals are used by plants to interfere with the growth or development of other plants or organisms, defensive chemicals can help plants in mycorrhizal networks defend themselves against attack by pathogens or herbivores, and transferred nutrients can affect growth and nutrition. Results of studies which demonstrate these modes of communication have led the authors to hypothesize mechanisms by which the transfer of these nutrients can affect the fitness of the connected plants.
References
- 1 2 "Rhabodocline Needlecast (Rhabdocline weirii)," Department of Plant Pathology, Cornell University. Retrieved 7 September 2007.
- ↑ "How To Identify and Control Rhabdocline and Swiss Needlecasts of Douglas-Fir," North Central Forest Experiment Station United States Forest Service, 1983. Retrieved 7 September 2007.