| Pythium graminicola | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Clade: | Diaphoretickes |
| Clade: | SAR |
| Clade: | Stramenopiles |
| Phylum: | Oomycota |
| Order: | Peronosporales |
| Family: | Pythiaceae |
| Genus: | Pythium |
| Species: | P. graminicola |
| Binomial name | |
| Pythium graminicola Subraman., (1928) | |
Pythium graminicola is a plant pathogen infecting cereals.
Pythium graminicola infects a wide range of hosts, including: bent grass, turmeric, cotton, barley, wheat, rice, beans, peas, and sugarcane. In particular Pythium graminicola is an important pathogen of graminaceous plants. [1] As with many Pythium diseases, the most common symptom of Pythium graminicola is root/seed rot, which can then cause damping off. However, Pythium graminicola can also infect above ground tissue causing stalk rot in maize, foot rot of beans, leaf blight of grasses and feeder root necrosis in rice, sugarcane and maize. [2] Diagnosis of Pythium graminicola can be made through observation of the above symptoms and the presence of oomycete structures, such as sporangia.
The life cycle of Pythium graminicola is essentially the same as the generalized Pythium, soil borne pathogen life cycle. In the sexual state of Pythium graminicola an antheridium and an oogonium combine to make an oospore. An oospore has a thick cell wall and can survive and overwinter either in the soil or on plant debris. These oospores act as the primary innoculum by remaining dormant for up to ten years and the germinating when conditions are right. Oospores can be disseminated by wind, or, if in the soil, can infect host seedlings causing systemic infection. The oospores that infect plants then create sporangia, the asexual state of Pythium graminicola, which acts as a secondary innoculum, making the disease cycle polycyclic. Sporangia can be disseminated by wind and produce zoospores, which act as the infection agent. Zoospores can swim a short distance in water using flagellum helping them to reach the host plant. Zoospores infect the host plant by adhering to the plant surface and then germinating into the host plant with hyphae. Pythium infects and spreads through roots very fast. Penetration occurs quickly, and the cell wall does not act as an important barrier to keep Pythium graminicola from infecting the plant. [3]
There are several current practices used to manage Pythium graminicola, including: chemical control, biological control, use of genetic resistance, and control through cultural practices. Chemical control involves using specific pesticides such as benomyl, captafol, captan, carboxin, metalaxyl, propamocarb hydrochloride, and etridiazole to try and kill surviving oospores in the soil. [4] Seeds can also be dipped into chemicals to protect them from seed rot and avoid damping off. Biological control involves using microorganisms that protect the plant roots by producing antifungal metabolites and competing with the pathogen for nutrients. [4] There are already commercially available biological control products for Pythium root rot created from isolates of Trichoderma spp. and Gliocladium spp., which are antagonists of Pythium-induced soil-borne diseases. [4] Genetic resistance involves finding species of plant that are not susceptible to Pythium graminicola. Cultural practice is a broad category that essential includes any practice that does not use the above controls methods. An example of cultural practice is avoiding growing crops in environments that the disease thrives in. Another example would be using composts with specific compositions, such as composts prepared from brewery sludge, Endicott biosolids, and some animal manures, to suppress damping-off and root rot. [5]
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.
Phytophthora palmivora is an oomycete that causes bud-rot of palms, fruit-rot or kole-roga of coconut and areca nut. These are among the most serious diseases caused by fungi and moulds in South India. It occurs almost every year in Malnad, Mysore, North & South Kanara, Malabar and other areas. Similar diseases of palms are also known to occur in Sri Lanka, Mauritius, and Sumatra. The causative organism was first identified as P. palmivora by Edwin John Butler in 1917.
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 fungal-like plant pathogen belonging to the Oomycota phylum. It is the causal agent of root rot on rhododendron and many other species, as well as leather rot of strawberries.
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.
Phytophthora nicotianae or black shank is an oomycete belonging to the order Peronosporales and family Peronosporaceae.
Pythium irregulare is a soil borne oomycete plant pathogen. Oomycetes, also known as "water molds", are fungal-like protists. They are fungal-like because of their similar life cycles, but differ in that the resting stage is diploid, they have coenocytic hyphae, a larger genome, cellulose in their cell walls instead of chitin, and contain zoospores and oospores.
Pythium ultimum is a plant pathogen. It causes 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.
Phytophthora erythroseptica—also known as pink rot along with several other species of Phytophthora—is a plant pathogen. It infects potatoes causing their tubers to turn pink and damages leaves. It also infects tulips (Tulipa) damaging their leaves and shoots.
Pythium aphanidermatum is a soil borne plant pathogen. Pythium is a genus in the class Oomycetes, which are also known as water molds. Oomycetes are not true fungi, as their cell walls are made of cellulose instead of chitin, they are diploid in their vegetative state, and they form coenocytic hyphae. Also, they reproduce asexually with motile biflagelette zoospores that require water to move towards and infect a host. Sexually, they reproduce with structures called antheridia, oogonia, and oospores.
Pythium aristosporum is a species of pythium under the class oomycota that causes root dysfunction in creeping bentgrass.
Pythium myriotylum is a soil-borne oomycete necrotroph that has a broad host range, this means that it can infect a wide range of plants.
Pythium volutum is a plant pathogen infecting wheat, barley, and turfgrass. It is known to be sensitive to some of the compounds typically present in selective media commonly used for isolating Pythium spp., so isolation may require alternative methods.
Sclerophthora macrospora is a protist plant pathogen of the class Oomycota. It causes downy mildew on a vast number of cereal crops including oats, rice, maize, and wheat as well as varieties of turf grass. The common names of the diseases associated with Sclerophthora macrospora include "crazy top disease" on maize and yellow tuft disease on turf grass. The disease is present all over the world, but it is especially persistent in Europe.
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.
Pythium dissotocum is a plant pathogen infecting strawberry and rice.
Phytophthora quercina is a papillate homothallic soil-borne plant pathogen causing root rot of oak tree species in Europe. It is associated with necrotic fine roots.
Buckeye rot of tomato is caused by three species of pathogens in the genus Phytophthora: P. nicotianae var. parasitica, P. capsici, and P. drechsleri. It is an oomycete that thrives in warm, wet conditions and lives in the soil. It is characterized by a bull’s eye pattern of dark brown rotting on the tomato fruit, and affects fruit that is close to, or lying on the soil. The easiest management is to keep the plant out of contact with the soil, although other chemical methods can be very effective. This disease commonly occurs in the southeast and south central areas of the United States. The disease has affected a large portion of crop yield in the United States as well as India. The relatively small genome size of Phytophthora parasitica compared to Phytophthora infestans gives researchers the unique ability to further examine its ability to cause disease.
Globisporangium sylvaticum is a plant pathogen, an oomycete known to cause root rot and damping off in a multitude of species. These species include apples, carrot, cherry laurel, cress, cucumber, garlic, lettuce, pea, rhododendron, and spinach. Symptoms of infection include stunting, wilt, chlorosis, and browning and eventual necrosis of roots. The pathogen can by identified by the presence of thick, microscopic, round spores within the cells of the root.
Black rot on orchids is caused by Pythium and Phytophthora species. Black rot targets a variety of orchids but Cattleya orchids are especially susceptible. Pythium ultimum and Phytophthora cactorum are known to cause black rot in orchids.