| Phytophthora megasperma | |
|---|---|
 | |
| Symptoms of Phytophthora megasperma on soybean | |
Scientific classification  | |
| Clade: | SAR |
| Phylum: | Oomycota |
| Order: | Peronosporales |
| Family: | Peronosporaceae |
| Genus: | Phytophthora |
| Species: | P. megasperma |
| Binomial name | |
| Phytophthora megasperma Drechsler, (1931) | |
| Synonyms | |
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Phytophthora megasperma is a species of water mould in the family Peronosporaceae. It is well known as a plant pathogen with many hosts. It often causes a plant disease called root rot. [1]
This is a poorly defined species which is generally called a species complex. Its name applies to water moulds of many forms, functions, and host preferences, many of which are actually different species which have not yet been separated and described. [2] [3] Some species previously treated as part of the complex include Phytophthora rosacearum , P. sansomeana , P. sojae , P. medicaginis , and P. trifolii . [3] A form of P. megasperma is suspected to be a separate species when it is recognized to have host specificity, when it is found attacking just one host plant; alfalfa in the case of P. medicaginis, for example. [2]
Water moulds in the P. megasperma complex can be found on a multitude of host plants, including many agricultural crops. It has been noted on soybeans, [4] kiwifruit (Actinidia deliciosa), horse chestnut (Aesculus hippocastanum), hollyhock (Alcea rosea), asparagus (Asparagus officinalis), Brassica oleracea , crops such as cabbage, cauliflower, safflower (Carthamus tinctorius), Port Orford cedar (Chamaecyparis lawsoniana), chickpea (Cicer arietinum), carrot (Daucus carota), carnation (Dianthus caryophyllus), eucalyptus (Eucalyptus spp.), walnut (Juglans regia), apple (Malus domestica), pines (Pinus spp.), stone fruit such as apricot, cherry, plum, and peach, Douglas fir (Pseudotsuga menziesii), sugarcane (Saccharum officinarum), and potato (Solanum tuberosum). [1]
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales.
Plant pathology is the scientific study of diseases in plants caused by pathogens and environmental conditions. Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are ectoparasites like insects, mites, vertebrate, or other pests that affect plant health by eating of plant tissues. Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases.
Phytophthora infestans is an oomycete or water mold, a microorganism that causes the serious potato and tomato disease known as late blight or potato blight. Early blight, caused by Alternaria solani, is also often called "potato blight". Late blight was a major culprit in the 1840s European, the 1845 - 1852 Irish, and the 1846 Highland potato famines. The organism can also infect some other members of the Solanaceae. The pathogen is favored by moist, cool environments: sporulation is optimal at 12–18 °C (54–64 °F) in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C (59 °F). Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C.
Phytophthora is a genus of plant-damaging oomycetes, whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural ecosystems. The cell wall of Phytophthora is made up of cellulose. The genus was first described by Heinrich Anton de Bary in 1875. Approximately 170 species have been described, although 100–500 undiscovered Phytophthora species are estimated to exist.
Phytophthora ramorum is the oomycete plant pathogen known to cause the disease sudden oak death (SOD). The disease kills oak and other species of trees and has had devastating effects on the oak populations in California and Oregon, as well as being present in Europe. Symptoms include bleeding cankers on the tree's trunk and dieback of the foliage, in many cases leading to the death of the tree.
Phytophthora cinnamomi is a soil-borne water mould that produces an infection which causes a condition in plants variously called "root rot", "dieback", or, "ink disease". The plant pathogen is one of the world's most invasive species and is present in over 70 countries around the world.
Pythium is a genus of parasitic oomycetes. They were formerly classified as fungi. Most species are plant parasites, but Pythium insidiosum is an important pathogen of animals, causing pythiosis. The feet of the fungus gnat are frequently a vector for their transmission.
Phytophthora sojae is an oomycete and a soil-borne plant pathogen that causes stem and root rot of soybean. This is a prevalent disease in most soybean growing regions, and a major cause of crop loss. In wet conditions the pathogen produces zoospores that move in water and are attracted to soybean roots. Zoospores can attach to roots, germinate, and infect the plant tissues. Diseased roots develop lesions that may spread up the stem and eventually kill the entire plant. Phytophthora sojae also produces oospores that can remain dormant in the soil over the winter, or longer, and germinate when conditions are favourable. Oospores may also be spread by animals or machinery.
Cercospora is a genus of ascomycete fungi. Most species have no known sexual stage, and when the sexual stage is identified, it is in the genus Mycosphaerella. Most species of this genus cause plant diseases, and form leaf spots. It is a relatively well-studied genus of fungus, but there are countless species not yet described, and there is still much to learn about the best-known of the species.
Damping off is a horticultural disease or condition, caused by several different pathogens that kill or weaken seeds or seedlings before or after they germinate. It is most prevalent in wet and cool conditions.
Aphanomyces euteiches is a water mould, or oomycete, plant pathogen responsible for the disease Aphanomyces root rot. The species Aphanomyces euteiches can infect a variety of legumes. Symptoms of the disease can differ among hosts but generally include reduced root volume and function, leading to stunting and chlorotic foliage. Aphanomyces root rot is an important agricultural disease in the United States, Europe, Australia, New Zealand, and Japan. Management includes using resistant crop varieties and having good soil drainage, as well as testing soil for the pathogen to avoid infected fields.
Phytophthora cactorum is a plant pathogen that causes root rot on rhododendron and many other species.
Phytophthora medicaginis is an oomycete plant pathogen that causes root rot in alfalfa and chickpea. It is a major disease of these plants and is found wherever they are grown. P. medicaginis causes failure of stand establishment because of seedling death. Phytophthora medicaginis is part of a species complex with Phytophthora megasperma.
Pythium ultimum is a plant pathogen. It causes the damping off and root rot diseases of hundreds of diverse plant hosts including corn, soybean, potato, wheat, fir, and many ornamental species. P. ultimum belongs to the peronosporalean lineage of oomycetes, along with other important plant pathogens such as Phytophthora spp. and many genera of downy mildews. P. ultimum is a frequent inhabitant of fields, freshwater ponds, and decomposing vegetation in most areas of the world. Contributing to the widespread distribution and persistence of P. ultimum is its ability to grow saprotrophically in soil and plant residue. This trait is also exhibited by most Pythium spp. but not by the related Phytophthora spp., which can only colonize living plant hosts.
Jarrah Forest is an interim Australian bioregion located in Western Australia. The Jarrah Forest comprises reserves across the south-west corner of WA and is managed for uses including recreation. There are many small areas of parkland while larger protected areas include the Dryandra Woodland, Lane-Poole Reserve, and the Perup Forest Ecology Centre. Also managed for land uses such as water, timber and mineral production, recreation and conservation, the forest is recognised globally as a significant hotspot of plant biodiversity and endemism.
Phytophthora capsici is an oomycete plant pathogen that causes blight and fruit rot of peppers and other important commercial crops. It was first described by L. Leonian at the New Mexico State University Agricultural Experiment Station in Las Cruces in 1922 on a crop of chili peppers. In 1967, a study by M. M. Satour and E. E. Butler found 45 species of cultivated plants and weeds susceptible to P. capsici In Greek, Phytophthora capsici means "plant destroyer of capsicums". P. capsici has a wide range of hosts including members of the families Solanaceae and Cucurbitaceae as well as Fabaceae.
Diaporthe phaseolorum var. caulivora is a fungal plant pathogen which infects soybean, causing soybean stem canker.
Cercospora kikuchii is a fungal plant pathogen that affects soybeans. It results in both the Cercospora leaf blight and purple seed stain diseases on soybean and is found almost worldwide. C. kikuchii produces the toxin cercosporin, as do a number of other Cercospora species.
Pratylenchus is a genus of nematodes known commonly as lesion nematodes. They are parasitic on plants and are responsible for root lesion disease on many taxa of host plants in temperate regions around the world. Lesion nematodes are migratory endoparasites that feed and reproduce in the root and move around, unlike the cyst or root-knot nematodes, which may stay in one place. They usually only feed on the cortex of the root. Species are distinguished primarily by the morphology of the stylets.
Human interactions with fungi include both beneficial uses, whether practical or symbolic, and harmful interactions such as when fungi damage crops, timber, or food.
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