| Pecan antharacnose | |
|---|---|
| Causal agents | Glomerella cingulata |
| Hosts | Pecan trees |
| EPPO Code | GLOMCI |
Pecan anthracnose is a fungal disease of pecan trees caused by the ascomycete Glomerella cingulata (Stoneman) Spauld. & H. It is a widespread disease found wherever pecan trees are grown. Pecan anthracnose has been reported as far back in time as 1914 (Rand 1914), [1] and as far away as Argentina (Mantz, Minhot et al. 2010). [2] Glomerella cingulata has two anamorphs which cause disease on pecan trees, Colletotrichum gloeosporioides and Colletotrichum acutatum (Latham 1995). [3] The occurrence of Colletotrichum on pecans has contributed to a significant decline in pecan production in various years. An increase in the incidence of pecan anthracnose is highly correlated with heavy rainfall, especially heavy rainfall occurring in early spring. The severity of symptoms increases as the season progresses, often culminating in leaf drop in the late autumn. This defoliation is linked to lower yield and poorer quality of nuts (Brenneman 2010). [4]
Pecan anthracnose is caused by the fungus Glomerella cingulata and is a disease of pecan trees that causes significant losses of yields as it attacks the nut itself. Pecan anthracnose is favored by wet environmental conditions and warm temperatures above 80 degrees Fahrenheit. [5] Symptoms include dark lesions on the pecan shuck and leaves. The lesions can grow over the entire plant. Signs include pink spores inside of the lesions. [5] If left untreated, symptoms will get progressively worse throughout the season, progressively reducing yield. Pecans are primarily grown in the southern part of the United States, [6] so these warm, wet areas are most susceptible to pecan anthracnose. Pecan anthracnose can occasionally cause zinc deficiencies in the trees it infects; of the cultivars of pecans that are susceptible, Witchita, [7] Kiowa, Gloria Grande, Pawnee and Mohawk are most prone to zinc deficiencies. [5] Pecan anthracnose can significantly cost farmers; the disease causes infected trees to produce less nuts and or drop them too early. Additionally, like mentioned above, the lesions of the disease can grow to cover the entirety of a fruit, making the pecan crop unsellable and unconsumable. It is estimated that pecan anthracnose cost Georgia farmers 3.4 million dollars in 2009.
For pecan anthracnose, it is best to use a similar control method to that used against pecan scab. [5] Both pecan scab and anthracnose are best controlled by making sure the plants get plenty of airflow to keep their environment dry (one way to do this is by making sure the plants are not crowded together). [8] Additionally, it is important to remove the dead leaves, nuts, etc. from the past season because the pathogen can overwinter in these structures and strike again the following year). [7] Another form of control involves spraying fungicide 7–12 times throughout the season, beginning in the spring. As a preventative measure it is important to spray fungicide as soon as the bud breaks. Spraying fungicide also helps to ward off powdery mildew and pecan scab. In 2012, it was found that compounds created from Lactobacillus plantarum had important antifungal properties that could be used to treat pecan anthracnose caused by Glomerella cingulate. [9] As far as prevention goes, there are some varieties of pecan plants that are resistant to anthracnose and pruning out and destroying diseased plants can help to stop the spread of the disease.
Pecan anthracnose is an ascomycete fungus and has a life cycle similar to that of other ascomycetes. [10] [11] Anthracnose has an overwintering stage and survives as an ascocarp. The ascocarp can survive on fallen nuts, leaves and other plant debris. Ascocarps can be spread by the wind or rain. Then, during a rainy, warm spring or summer, the ascocarp releases its ascospores and they go off and infect new plants to create more ascocarps which in turn make more ascospores and the life cycle begins again. [12] Anthracnose is polycyclic, so it has a sexual stage as conidia when it finds its mating type. [11]
The financial loss due to pecan anthracnose in 2009 in Georgia was estimated at US$3.4 million (Brock 2010). [13] However, the actual loss due to the disease is difficult to quantify. Due to the nature of carbohydrate storage in perennials, the damage to pecan production is also likely to present itself in a lower yield in the year directly following a disease outbreak (Worley 1979). [14]
Pecan anthracnose is reported to have an unusually long latent period; it can take weeks to months from the time of initial infection to symptom development. Both ascospores and conidia can be found in the field and in culture, and both of these spore types can cause infection (Rand 1914). [1]
Pink conidial oozes can be observed emerging from acervuli with setae on leaves and shucks.
Powdery mildew is a fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of fungi in the order Erysiphales. Powdery mildew is one of the easier plant diseases to identify, as its symptoms are quite distinctive. Infected plants display white powdery spots on the leaves and stems. The lower leaves are the most affected, but the mildew can appear on any above-ground part of the plant. As the disease progresses, the spots get larger and denser as large numbers of asexual spores are formed, and the mildew may spread up and down the length of the plant.
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, where 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.
Venturia inaequalis is an ascomycete fungus that causes the apple scab disease.
Glomerella graminicola is an economically important crop parasite affecting both wheat and maize where it cause the plant disease Anthracnose Leaf Blight . Certain cereal varieties that have been genetically engineered. may be more susceptible to the teleomorph phase of the fungus.
Colletotrichum acutatum is a plant pathogen. It is the organism that causes the most destructive fungal disease, anthracnose, of lupin species worldwide. It also causes the disease postbloom fruit drop on many varieties of citrus, especially Valencia and navel oranges in Florida.
Leptosphaeria coniothyrium is a plant pathogen. It can be found across the world.
Colletotrichum kahawae is a fungal plant pathogen that causes coffee berry disease (CBD) on Coffea arabica crops. The pathogen is an ascomycete that reproduces asexually. The asexual spores (conidia) are stored within acervuli. This disease is considered to be one of the major factors hampering C.arabica production in the African continent, which represents the current geographic range of the fungus. Coffee berry disease causes dark necrosis in spots and causes the green berries of the coffee to drop prematurely. High humidity, relatively warm temperatures, and high altitude are ideal for disease formation. Given the severity of the disease and the lack of effective control measures, there is great concern that the fungus may spread to other coffee producing continents, such as South America, which could have catastrophic consequences.
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.
Mycosphaerella angulata is a fungal plant pathogen infecting muscadine grapes. This pathogen causes the common disease angular leaf spot. Mycosphaerella angulate is a ascomycete in the fungi kingdom.
Elsinoë mangiferae, common name Mango Scab, is also known Denticularia mangiferae or Sphaceloma mangiferae (anamorph). It is an ascomycete plant pathogen native to tropical regions and specific for survival on only one host, the mango. Originally described in 1943 from Florida and Cuba specimens, this pathogen has since spread worldwide and is becoming a pathogen of great concern for the mango industries in Australia and India. The species was first described formally in 1946.
Sphaceloma perseae is a plant-pathogenic fungus in the division Ascomycota. It infects the avocado plant, a tree native to Central America and Mexico. Currently there are three cultivars of avocados in large-scale agricultural production: Guatemalan, Mexican, and West Indian. The pathogen is currently limited to the P. Americana species but is able to infect all three cultivars. The resulting disease is known as avocado scab for the symptoms which are present on the fruit of the avocado tree. It is believed that the disease developed in Florida in the early twentieth century and is related to citrus scab, Elsinoe fawcetti. Since then, S.perseae has spread to many regions worldwide that support cultivation of the avocado tree. This pathogen threatens the global avocado market, including both importers and exporters of the crop. Countries which import avocados, including the United States, have experienced a rising demand over the past decade which is projected to continue for years to come. An understanding of avocado scab characteristics and feasible prevention methods is essential to maintenance of cultures and economies influenced by the avocado fruit.
Didymella bryoniae, syn. Mycosphaerella melonis, is an ascomycete fungal plant pathogen that causes Gummy stem blight on the family Cucurbitaceae [1-3]. The anamorph/asexual stage for this fungus is called Phoma cucurbitacearum[2]. This pathogen commonly affects the foliage and stems of plants from the family Cucurbitaceae, which includes cantaloupe, cucumber, muskmelon and watermelon plants [1,3,8]. When this pathogen infects the fruit of cucurbits it is called black rot [2].
Colletotrichum coccodes is a plant pathogen, which causes anthracnose on tomato and black dot disease of potato. Fungi survive on crop debris and disease emergence is favored by warm temperatures and wet weather.
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Elsinoë ampelina is a plant pathogen, which is the causal agent of anthracnose on grape.
Colletotrichum cereale is a plant disease (fungus) that has been found to cause crown rot anthracnose of turf grass most commonly occurring on golf courses. Anthracnose can occur as both a foliar blight and basal rot. This disease attacks the crowns of plants, which is different than other anthracnose diseases. Anthracnose of turfgrass can be a foliar disease or in this case a basal rot of the lower portion of the plant. It attacks different species of turfgrass throughout the world most commonly annual bluegrass and creeping bentgrass.
Taphrina caerulescens is a species of fungus in the family Taphrinaceae. It is a pathogenic Ascomycete fungus that causes oak leaf blister disease on various species of oak trees. The associated anamorph species is Lalaria coccinea, described in 1990. This disease causes lesions and blisters on Oak leaves. Effects of the disease are mostly cosmetic. Although not taxonomically defined, strains of T. caerulescens have been shown to be host specific with varying ¬ascus morphology between strains. There are differences in strains’ abilities to metabolize various carbon and nitrogen compounds. This has been proposed as a method of taxonomically defining subspecies within T. caerulescens.
Pecan scab is the most economically significant disease of pecan trees in the southeastern United States. Venturia effusa is a fungal plant pathogen that causes pecan scab. The fungus causes lesions and tissue death on pecan twigs, petioles, leaves, nuts and shucks beginning in early spring, with multiple cycles of infection repeating until late summer. Wind and rain spread the fungus to a susceptible host. Control of the disease is achieved by fungicide, sanitation and, in some cases, quarantine.
