Septoria cannabis | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Dothideomycetes |
Order: | Capnodiales |
Family: | Mycosphaerellaceae |
Genus: | Septoria |
Species: | S. cannabis |
Binomial name | |
Septoria cannabis (Lasch) Sacc., (1884) | |
Synonyms | |
Ascochyta cannabisLasch, in Klotzsch (1846) Contents |
Septoria cannabis is a species of plant pathogen from the genus Septoria that causes the disease commonly known as Septoria leaf spot. Early symptoms of infection are concentric white lesions on the vegetative leaves of cannabis plants, followed by chlorosis and necrosis of the leaf until it is ultimately overcome by disease and all living cells are then killed. Septoria, which is an ascomycete and pycnidia producing fungus, has been well known to attack Solanaceae and Cucurbitaceae species as well as many tree species. This genus is known to comprise over 1,000 species of pathogens, each infecting a specific and unique host.
This disease only infects cannabis or hemp plants. Symptomatic responses associated with this disease will be in the form of white lesions with concentric rings on the surface of the plants vegetative leaves, as well as browning and chlorosis on infected leaves. [1] The first symptoms of this disease will occur on the older, lower leaves of the plant. Septoria has been known to spread rapidly within a growing season and will eventually attack all of the cannabis’ vegetative growth rendering it unable to perform any biological processes and ultimately die. If the disease is extreme most vegetative tissue will be destroyed, taking away the cannabis plant’s source of sugars and ultimately turning the entire host into a sink and reducing yields come harvest. Nitrogen deficient cannabis plants are more susceptible to being infected. [2] Though Septoria destroys vegetative growth it has little to no impact on the formation of buds. This disease was discovered in New York dating back to 1884, and was recently found and studied in North Carolina. [3]
The disease cycle for Septoriacannabis is identical to that of Septoriatritici [4] or Septoria of tomato [5] except for the production of a perithecium instead of a pseudothecium. Being that it is a polycyclic disease, it can asexually produce conidia in a pycnidium which continually inoculates new hosts throughout the growing season, as well as sexually produce ascospores in a perithecium which acts as an overwintering structure. [4] The disease survives on plant debris from the previous growing season as ascospores in a perithecium, as well as mycelium on the epidermal tissue layers of leaves. The thick cell wall of the ascospores provides protection and allows for the disease to remain in the infected growing area until favorable conditions return. [4] When the conditions are favorable (summer-fall) the spores are released and carried by wind or raindrops to a nearby host. [4] Once infected the disease quickly spreads via the production of conidia in the secondary cycle which is accompanied by the sexual production of ascospores. Pycnidium are formed on the leaf lesions.[ citation needed ]
Septoria is present in many parts of the world, but has only become prevalent in the marijuana industry with the movement towards legalization. Ranging from the Emerald Triangle in California, to the cold winds of the east coast, Septoria is becoming an increasing nuisance for cannabis growers. Like most Septoria species they require moist and humid conditions to germinate, because of their conidia being immotile, and survive during the off-season by overwintering on dead and decaying organic matter. [4] The disease moves to other parts of the plant during periods of rain or heavy wind, which enable the dispersal of ascospores (primary cycle) and conidia (secondary cycle) to roam and infect other vegetative tissue. [6]
Survival decreases dramatically in hot weather. When buried in soil (i.e. tilling), conidial structures survive less than one month. [7]
The management associated with Septoria of tomato is very similar to that of Septoriacannabis. To avoid this disease, a grower must eliminate survival structures which are dead and decaying leaves or organic matter around the area which you are growing. [6] Sanitation of the growing area can make all of the difference when battling diseases of any nature. Many diseases like Septoria thrive in an area that provides excess decaying material; by removing dead leaves the pathogen with fewer survival structures. Since Septoria relies on the proximity of suitable hosts, increasing the spacing of cannabis plants and rotating crops annually will decrease the likelihood that the disease will move next door. [6] The use of fungicides (Bordeaux Mixture, or Daconil 2787) [5] is also applicable when the disease has infected plants. Good practices such as avoiding overhead irrigation, especially before dusk, will decrease the amount of stagnant water on leaves that can trap windblown conidia spores. Eliminating survival structures that ascospores rely on is the most important aspect in disease control for Septoria and this can be accomplished by covering the growing area in mulch or burying/disposing plant debris.[ citation needed ]
Pyrenophora teres is a necrotrophic fungal pathogen of some plant species, the most significant of which are economically important agricultural crops such as barley. Toxins include aspergillomarasmine A and related compounds.
Blumeria graminis is a fungus that causes powdery mildew on grasses, including cereals. It is the only species in the genus Blumeria. It has also been called Erysiphe graminis and Oidium monilioides or Oidium tritici.
Phomopsis cane and leaf spot occurs wherever grapes are grown. Phomopsis cane and leaf spot is more severe in grape-growing regions characterized by a humid temperate climate through the growing season. Crop losses up to 30% have been reported to be caused by Phomopsis cane and leaf spot.
Pseudocercosporella capsellae is a plant pathogen infecting crucifers. P. capsellae is the causal pathogen of white leaf spot disease, which is an economically significant disease in global agriculture. P. capsellae has a significant effect on crop yields on agricultural products, such as canola seed and rapeseed. Researchers are working hard to find effective methods of controlling this plant pathogen, using cultural control, genetic resistance, and chemical control practices. Due to its rapidly changing genome, P. capsellae is a rapidly emerging plant pathogen that is beginning to spread globally and affect farmers around the world.
Erysiphe cruciferarum is a plant pathogen of the family Erysiphaceae, which causes the main powdery mildew of crucifers, including on Brassica crops, such as cauliflower, cabbage, broccoli, and Brussels sprouts. E. cruciferarum is distributed worldwide, and is of particular concentration in continental Europe and the Indian subcontinent. E. cruciferarum is an ascomycete fungus that has both sexual and asexual stages. It is also an obligate parasite that appears to have host specificity; for example, isolates from turnip will not infect Brussels sprout, and vice versa. While being a part of the family Erysiphaceae, it belongs to those members in which the conidia are formed singly and whose haustoria are multilobed.
Mycosphaerella brassicicola is a plant pathogen. The pathogen is the teleomorph phase of an ascomycete fungus, which causes the ring spot disease of brassicas. The supplementary anamorph phase Asteromella brassicae produces conidia through its asexual reproduction, however these spores are not confirmed to cause disease in host plants.
Pyrenophora tritici-repentis (teleomorph) and Drechslera tritici-repentis (anamorph) is a necrotrophic plant pathogen of fungal origin, phylum Ascomycota. The pathogen causes a disease originally named yellow spot but now commonly called tan spot, yellow leaf spot, yellow leaf blotch or helminthosporiosis. At least eight races of the pathogen are known to occur based on their virulence on a wheat differential set.
Zymoseptoria tritici, synonyms Septoria tritici, Mycosphaerella graminicola, is a species of filamentous fungus, an ascomycete in the family Mycosphaerellaceae. It is a wheat plant pathogen causing septoria leaf blotch that is difficult to control due to resistance to multiple fungicides. The pathogen today causes one of the most important diseases of wheat.
Podosphaera macularis is a plant pathogen infecting several hosts including chamomile, caneberrie, strawberries, hop, hemp and Cineraria. It causes powdery mildew of hops.
Stemphylium solani is a plant pathogen fungus in the phylum Ascomycota. It is the causal pathogen for grey leaf spot in tomatoes and leaf blight in alliums and cotton, though a wide range of additional species can serve as hosts. Symptoms include white spots on leaves and stems that progress to sunken red or purple lesions and finally leaf necrosis. S. solani reproduces and spreads through the formation of conidia on conidiophores. The teleomorph name of Stemphyllium is Pleospora though there are no naturally known occurrences of sexual reproduction. Resistant varieties of tomato and cotton are common, though the pathogen remains an important disease in Chinese garlic cultivation.
Diplocarpon earlianum is a species of fungus that causes disease in strawberry plants called strawberry leaf scorch. The disease overwinters in plant debris and infects strawberry plants during the spring season when it is wet. The five main methods to reduce strawberry leaf scorch include: irrigation techniques, crop rotation, planting resistant and disease-free seeds, fungicide use, and sanitation measures. Control of strawberry leaf scorch is important because it is responsible for the majority of disease in strawberries. Diplocarpon earliana affects the fruit quality and yield of the strawberry crop. Losses range from negligible to severe depending on numerous epidemiological factors including cultivar susceptibility, type of cropping system, and weather conditions
Ascochyta is a genus of ascomycete fungi, containing several species that are pathogenic to plants, particularly cereal crops. The taxonomy of this genus is still incomplete. The genus was first described in 1830 by Marie-Anne Libert, who regarded the spores as minute asci and the cell contents as spherical spores. Numerous revisions to the members of the genus and its description were made for the next several years. Species that are plant pathogenic on cereals include, A. hordei, A. graminea, A. sorghi, A. tritici. Symptoms are usually elliptical spots that are initially chlorotic and later become a necrotic brown. Management includes fungicide applications and sanitation of diseased plant tissue debris.
Ascochyta pisi is a fungal plant pathogen that causes ascochyta blight on pea, causing lesions of stems, leaves, and pods. These same symptoms can also be caused by Ascochyta pinodes, and the two fungi are not easily distinguishable.
Peronosclerospora sorghi is a plant pathogen. It is the causal agent of sorghum downy mildew. The pathogen is a fungal-like protist in the oomycota, or water mold, class. Peronosclerospora sorghi infects susceptible plants though sexual oospores, which survive in the soil, and asexual sporangia which are disseminated by wind. Symptoms of sorghum downy mildew include chlorosis, shredding of leaves, and death. Peronosclerospora sorghi infects maize and sorghum around the world, but causes the most severe yield reductions in Africa. The disease is controlled mainly through genetic resistance, chemical control, crop rotation, and strategic timing of planting.
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Rhytisma acerinum is a plant pathogen that commonly affects sycamores and maples in late summer and autumn, causing tar spot. Tar spot does not usually have an adverse effect on the trees' long-term health. R. acerinum is an Ascomycete fungus that locally infects the leaves of trees and is a biotrophic parasite. The disease is cosmetic and is therefore usually controlled only with sanitation methods.
Southern corn leaf blight (SCLB) is a fungal disease of maize caused by the plant pathogen Bipolaris maydis.
Raspberry leaf spot is a plant disease caused by Sphaerulina rubi, an ascomycete fungus. Early symptoms of infection are dark green spots on young leaves. As the disease progresses, these spots turn tan or gray in color. Disease management strategies for raspberry leaf spots include the use of genetically resistant raspberry plant varieties, chemical fungicide sprays, and cultural practices such as pruning and thinning out canes.
Gummy stem blight is a cucurbit-rot disease caused by the fungal plant pathogen Didymella bryoniae. Gummy stem blight can affect a host at any stage of growth in its development and affects all parts of the host including leaves, stems and fruits. Symptoms generally consist of circular dark tan lesions that blight the leaf, water soaked leaves, stem cankers, and gummy brown ooze that exudes from cankers, giving it the name gummy stem blight. Gummy stem blight reduces yields of edible cucurbits by devastating the vines and leaves and rotting the fruits. There are various methods to control gummy stem blight, including use of treated seed, crop rotation, using preventative fungicides, eradication of diseased material, and deep plowing previous debris.