| Mycosphaerella berkeleyi | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Dothideomycetes |
| Order: | Capnodiales |
| Family: | Mycosphaerellaceae |
| Genus: | Mycosphaerella |
| Species: | M. berkeleyi |
| Binomial name | |
| Mycosphaerella berkeleyi W.A. Jenkins, (1938) | |
| Synonyms | |
Cercospora personata(Berk. & M.A. Curtis) Ellis, (1885) Contents | |
Mycosphaerella berkeleyi is a fungal plant pathogen. It is the causal agent of the peanut foliar disease Late Leaf Spot.
Hosts that suffer from late leaf spot include groundnut species belonging to the genus Arachis hypogaea, [1] and peanuts. Late leaf spot of peanut that produces sexual spores is referred to as Mycosphaerella berkeleyi, whereas the asexual spore is referred to as Cercosporidium personatum. [1] Late leaf spot of peanut symptoms usually appear between 30–50 days following planting. [2] Symptoms include dark brown to black pin-point spots on the upper and under side of the leaf surface. This contrasts the fewer, lighter brown spots that early leaf spot of peanut presents. [2] Late leaf spot of peanut produces symptoms later in the season. These spores can be seen without magnification and give the spot a velvety appearance as opposed to early leaf spot of peanut, which can be seen with higher magnification. [3] Even though these differences are slight, it is what helps to distinguish between the two pathogens.
Late leaf spot of peanut is a serious disease that occurs in places where peanuts are grown worldwide. This foliar disease causes significant yield loss, and can be found wherever peanuts are grown. This includes areas such as Oklahoma, the southern USA, Fiji, Solomon Islands, as well as Tonga. [3] Infection causes early death of the leaves and dramatic yield loss. [3] This is estimated to range from 10% to 80%, [4] and varies according to the environment and availability of control methods. In the USA, where fungicide application is a typical management practice, yield losses are less frequent as opposed to the semi-arid tropics, where fungicides are less available. It is estimated that Cercosporidium personatum reduces yields by 50% or more in Pacific island countries. [3] Therefore, early detection is crucial, and successful management efforts must be implemented once the disease has been recognized. To help achieve this, early symptom recognition, as well as the timing of management strategies are valuable.
Cultural controls help to delay the onset and development of symptoms, and reduce the level of the primary inoculum present. [2] The primary inoculum that causes the onset of symptoms is induced by the production of microscopic spores called conidia in soil residue. [5] Large amounts of peanut residue in fields where peanuts are cropped seasonally usually results in the progression of late leaf spot. [5] Therefore, crop rotation, along with tillage practices are advised. [2] Since longer periods of leaf wetness is required for disease development, frequent irrigation can increase the chances of high humidity and increased leaf wetness. [5] As opposed to irrigation systems, growers are encouraged to apply small amounts of water regularly in order to maintain a drier canopy. [2] When planting new crops, plant as far away as possible, since late leaf spot spores travel far distances through wind dispersal. Try to avoid planting crops downwind from one another due to spore’s ability to travel between neighboring crop fields. [1] Different varieties of peanut differ in their reaction to the pathogen, but none have proven to be resistant, and are able to be used as a control method. [2] Spanish varieties are most susceptible, Virginia varieties are intermediates, and runner varieties are partially resistant. [2] Very specific chemical controls are used to prevent yield loss, and are required in a very narrow, specific time period in order to be most effective. To be most successful, spray chemical controls as soon as the onset of symptom development. [1] Fungicide application is recommended on a 14-day set calendar schedule, or according to weather based leaf spot advisory. [3] In fields that utilize crop rotation, fungicides should be sprayed during the early pod stage (R3), which typically occurs during July, but can vary according to environment. [3] After the first spray, the grower should continue to apply fungicides every 14 days or according to the leaf spot advisory. [3] Chlorothalonil (Bravo; various generic brands), are the most successful fungicides, and have reduced risk of host resistance. [6] An alternative approach to calendar sprays are to spray crops based on weather patterns. However, this method has proven to be less effective than calendar treatment approaches. Following a harvesting season, growers should collect, burn, or bury the remains of the crops to prevent the soil-borne pathogen from surviving and causing future disease outbreaks. [1]
Black sigatoka is a leaf-spot disease of banana plants caused by the ascomycete fungus Mycosphaerella fijiensis (Morelet), also known as black leaf streak. It was discovered in 1963 and named for its similarities with yellow Sigatoka, which is caused by Mycosphaerella musicola (Mulder), which was itself named after the Sigatoka Valley in Fiji. In the same valley an outbreak of this disease reached epidemic proportions from 1912 to 1923.
Apple scab is a common disease of plants in the rose family (Rosaceae) that is caused by the ascomycete fungus Venturia inaequalis. While this disease affects several plant genera, including Sorbus, Cotoneaster, and Pyrus, it is most commonly associated with the infection of Malus trees, including species of flowering crabapple, as well as cultivated apple. The first symptoms of this disease are found in the foliage, blossoms, and developing fruits of affected trees, which develop dark, irregularly-shaped lesions upon infection. Although apple scab rarely kills its host, infection typically leads to fruit deformation and premature leaf and fruit drop, which enhance the susceptibility of the host plant to abiotic stress and secondary infection. The reduction of fruit quality and yield may result in crop losses of up to 70%, posing a significant threat to the profitability of apple producers. To reduce scab-related yield losses, growers often combine preventive practices, including sanitation and resistance breeding, with reactive measures, such as targeted fungicide or biocontrol treatments, to prevent the incidence and spread of apple scab in their crops.
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.
Venturia inaequalis is an ascomycete fungus that causes the apple scab disease.
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.
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.
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.
Cercospora arachidicola is a fungal ascomycete plant pathogen that causes early leaf spot of peanut. Peanuts originated in South America and are cultivated globally in warm, temperate and tropical regions.
Mycosphaerella angulata is a fungal plant pathogen infecting muscadine grapes. This pathogen causes the common disease angular leaf spot. Mycosphaerella angulate is an ascomycete in the fungi kingdom.
Alternaria solani is a fungal pathogen that produces a disease in tomato and potato plants called early blight. The pathogen produces distinctive "bullseye" patterned leaf spots and can also cause stem lesions and fruit rot on tomato and tuber blight on potato. Despite the name "early," foliar symptoms usually occur on older leaves. If uncontrolled, early blight can cause significant yield reductions. Primary methods of controlling this disease include preventing long periods of wetness on leaf surfaces and applying fungicides. Early blight can also be caused by Alternaria tomatophila, which is more virulent on stems and leaves of tomato plants than Alternaria solani.
Sphaceloma arachidis is a plant pathogen infecting peanuts.
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.
This article summarizes different crops, what common fungal problems they have, and how fungicide should be used in order to mitigate damage and crop loss. This page also covers how specific fungal infections affect crops present in the United States.
Grey leaf spot (GLS) is a foliar fungal disease that affects maize, also known as corn. GLS is considered one of the most significant yield-limiting diseases of corn worldwide. There are two fungal pathogens that cause GLS: Cercospora zeae-maydis and Cercospora zeina. Symptoms seen on corn include leaf lesions, discoloration (chlorosis), and foliar blight. Distinct symptoms of GLS are rectangular, brown to gray necrotic lesions that run parallel to the leaf, spanning the spaces between the secondary leaf veins. The fungus survives in the debris of topsoil and infects healthy crops via asexual spores called conidia. Environmental conditions that best suit infection and growth include moist, humid, and warm climates. Poor airflow, low sunlight, overcrowding, improper soil nutrient and irrigation management, and poor soil drainage can all contribute to the propagation of the disease. Management techniques include crop resistance, crop rotation, residue management, use of fungicides, and weed control. The purpose of disease management is to prevent the amount of secondary disease cycles as well as to protect leaf area from damage prior to grain formation. Corn grey leaf spot is an important disease of corn production in the United States, economically significant throughout the Midwest and Mid-Atlantic regions. However, it is also prevalent in Africa, Central America, China, Europe, India, Mexico, the Philippines, northern South America, and Southeast Asia. The teleomorph of Cercospora zeae-maydis is assumed to be Mycosphaerella sp.
Ascochyta blights occur throughout the world and can be of significant economic importance. Three fungi contribute to the ascochyta blight disease complex of pea. Ascochyta pinodes causes Mycosphaerella blight. Ascochyta pinodella causes Ascochyta foot rot, and Ascochyta pisi causes Ascochyta blight and pod spot. Of the three fungi, Ascochyta pinodes is of the most importance. These diseases are conducive under wet and humid conditions and can cause a yield loss of up to fifty percent if left uncontrolled. The best method to control ascochyta blights of pea is to reduce the amount of primary inoculum through sanitation, crop-rotation, and altering the sowing date. Other methods—chemical control, biological control, and development of resistant varieties—may also be used to effectively control ascochyta diseases.
Common spot of strawberry is one of the most common and widespread diseases afflicting the strawberry. Common spot of strawberry is caused by the fungus Mycosphaerella fragariae. Symptoms of this disease first appear as circular, dark purple spots on the leaf surface. Mycosphaerella fragariae is very host-specific and only infects strawberry.
Cherry leaf spot is a fungal disease which infects cherries and plums. Sweet, sour, and ornamental cherries are susceptible to the disease, being most prevalent in sour cherries. The variety of sour cherries that is the most susceptible are the English morello cherries. This is considered a serious disease in the Midwest, New England states, and Canada. It has also been estimated to infect 80 percent of orchards in the Eastern states. It must be controlled yearly to avoid a significant loss of the crop. If not controlled properly, the disease can dramatically reduce yields by nearly 100 percent. The disease is also known as yellow leaf or shothole disease to cherry growers due to the characteristic yellowing leaves and shot holes present in the leaves upon severe infection.
Banana freckle is a disease caused by the fungus Guignardia musae (teleomorph) or Phyllosticta musarum (anamorph). Generally, the causal agent of disease is referred to as Guignardia-Phyllosticta sp. There are several different strains of the fungus that exist to infect different banana varieties around the globe. Symptoms include yellowing of the tissue and formation of small dark brown spots on the leaves and fruit. Within the spots, conidia or pycnidia can be found. Banana freckle is easily propagated and spread from plant to plant by rain splash and movement of infected tissue or fruit. Management of the disease consists of cutting out infected leaves, using the paper bag method, fungicide application, and proper sanitation techniques it can be stopped by applying vegeta to it. This devastating disease is extremely relevant for the major banana exporting countries of the world. In the absence of chemical control, there is about a 78% yield loss. Banana freckle disease needs to be carefully monitored in order to prevent further spread of the disease.
Alternaria black spot of canola or grey leaf spot is an ascomycete fungal disease caused by a group of pathogens including: Alternaria brassicae, A. alternata and A. raphani. This pathogen is characterized by dark, sunken lesions of various size on all parts of the plant, including the leaves, stem, and pods. Its primary economic host is canola. In its early stages it only affects the plants slightly by reducing photosynthesis, however as the plant matures it can cause damage to the seeds and more, reducing oil yield as well.
Puccinia sorghi, or common rust of maize, is a species of rust fungus that infects corn and species from the plant genus Oxalis.