Particular species of oomycetes are responsible for root rot.ĭespite not being closely related to the fungi, the oomycetes have developed similar infection strategies. They include some of the most destructive plant pathogens including the genus Phytophthora, which includes the causal agents of potato late blight and sudden oak death. (honey fungus species, virulent pathogens of trees)įungus-like organisms Oomycetes (canker rot, black root rot, Thielaviopsis root rot) Rice blast, caused by a necrotrophic fungus Ascomycetes Significant fungal plant pathogens include: Necrotrophic fungal pathogens infect and kill host tissue and extract nutrients from the dead host cells. However, new races of fungi often evolve that are resistant to various fungicides.īiotrophic fungal pathogens colonize living plant tissue and obtain nutrients from living host cells.
These are facultative saprotrophs.įungal diseases may be controlled through the use of fungicides and other agriculture practices. Many soil inhabiting fungi are capable of living saprotrophically, carrying out the part of their life cycle in the soil. Spores may be spread long distances by air or water, or they may be soil borne. The fungi reproduce both sexually and asexually via the production of spores and other structures. Most phytopathogenic fungi belong to the phyla Ascomycota and Basidiomycota. Many pathogens also grow opportunistically when the host breaks down its own cell walls, most often during fruit ripening. For microbes the cell wall polysaccharides are themselves a food source, but mostly just a barrier to be overcome. The vast majority of CWDPs are pathogen-produced and pectin-targeted (for example, pectinesterase, pectate lyase, and pectinases). In most pathosystems, virulence is dependent on hydrolases - and the wider class of cell wall degrading proteins - that degrade the cell wall. To solve this, new methods are needed to detect diseases and pests early, such as novel sensors that detect plant odours and spectroscopy and biophotonics that are able to diagnose plant health and metabolism. The Food and Agriculture Organization estimates that pests and diseases are responsible for about 25% of crop loss. Across large regions and many crop species, it is estimated that diseases typically reduce plant yields by 10% every year in more developed settings, but yield loss to diseases often exceeds 20% in less developed settings. Plant diseases cause major economic losses for farmers worldwide - see §Economic impact. Continuing advances in the science of plant pathology are needed to improve disease control, to keep up with the ongoing evolution and movement of plant pathogens, and to keep pace with changes in agricultural practices. It is achieved by use of plants that have been bred for good resistance to many diseases, and by plant cultivation approaches such as crop rotation, use of pathogen-free seed, appropriate planting date and plant density, control of field moisture, and application of pesticides. However, disease control is reasonably successful for most crops. Plants in both natural and cultivated populations carry inherent disease resistance, but there are numerous examples of devastating plant disease impacts, such as the Great Famine of Ireland and chestnut blight, as well as recurrent severe plant diseases like rice blast, soybean cyst nematode, and citrus canker. See also: Morphological symptoms of plant diseasesĬontrol of plant diseases is crucial to the reliable production of food, and it provides significant problems in agricultural use of land, water, fuel and other inputs.
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