The chestnuts are the deciduous trees and shrubs in the genus Castanea, in the beech family Fagaceae. The name also refers to the edible nuts they produce. They are native to temperate regions of the Northern Hemisphere.
The American chestnut is a large, fast-growing deciduous tree of the beech family native to eastern North America. As is true of all species in the genus Castanea, the American chestnut produces burred fruit with edible nuts. The American chestnut was once one of the most important forest trees throughout its range.
The pathogenic fungus Cryphonectria parasitica is a member of the Ascomycota. This necrotrophic fungus is native to East Asia and South East Asia and was introduced into Europe and North America in the early 1900s. The fungus spread rapidly and caused significant tree loss in both regions.
Dutch elm disease (DED) is caused by a member of the sac fungi (Ascomycota) affecting elm trees, and is spread by elm bark beetles. Believed to be originally native to Asia, the disease was accidentally introduced into America, Europe, and New Zealand. In these regions it has devastated native populations of elms that did not have resistance to the disease. The name "Dutch elm disease" refers to its identification in 1921 and later in the Netherlands by Dutch phytopathologists Bea Schwarz and Christine Buisman, who both worked with professor Johanna Westerdijk. The disease affects species in the genera Ulmus and Zelkova, therefore it is not specific to the Dutch elm hybrid.
Fire blight, also written fireblight, is a contagious disease affecting apples, pears, and some other members of the family Rosaceae. It is a serious concern to apple and pear producers. Under optimal conditions, it can destroy an entire orchard in a single growing season.
Citrus canker is a disease affecting Citrus species caused by the bacterium Xanthomonas. Infection causes lesions on the leaves, stems, and fruit of citrus trees, including lime, oranges, and grapefruit. While not harmful to humans, canker significantly affects the vitality of citrus trees, causing leaves and fruit to drop prematurely; a fruit infected with canker is safe to eat, but too unsightly to be sold. Citrus canker is mainly a leaf-spotting and rind-blemishing disease, but when conditions are highly favorable, it can cause defoliation, shoot dieback, and fruit drop.
The American Chestnut Foundation (TACF) is a nonprofit American organization dedicated to breeding a blight-resistant American chestnut tree and the reintroduction of this tree to the forests of the Eastern United States.
Ulmus 'Lobel' is a Dutch hybrid cultivar raised at the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen, from a crossing of clone '202' with '336'. 'Lobel' was cloned in 1962 and released for sale in 1973.
Ulmus 'Morton Red Tip' is a hybrid cultivar raised by the Morton Arboretum from an open pollination of Ulmus 'Morton'. The tree has occasionally been reported as a hybrid of Accolade with the Siberian Elm Ulmus pumila, an error probably owing to the commercial propagation of the tree by grafting onto U. pumila rootstocks. Tested in the US National Elm Trial coordinated by Colorado State University, Danada Charm averaged a survival rate of 77.5% after 10 years.
Ulmus 'Patriot' is a hybrid cultivar raised by the United States National Arboretum in 1980. Derived from a crossing of the American hybrid 'Urban' with the Wilson's Elm cultivar 'Prospector', 'Patriot' was released to commerce, free of patent restrictions, in 1993. Tested in the US National Elm Trial coordinated by Colorado State University, 'Patriot' averaged a survival rate of 85% after 10 years.
Ophiognomonia clavigignenti-juglandacearum is a mitosporic fungus that causes the butternut canker, a lethal disease of butternut trees. It is also known to parasitize other members of the genus Juglans on occasion, and very rarely other related trees including hickories. The fungus is found throughout North America, occurring on up to 91% of butternut trees, and may be threatening the viability of butternut as a species.
Anisogramma anomala is a plant pathogen that causes a disease known as Eastern filbert blight on Corylus spp. (hazlenut). Also known as EFB.
Bleeding canker of horse chestnut is a common canker of horse chestnut trees that is known to be caused by infection with several different pathogens.
The field elm cultivar Ulmus minor 'Majadahonda' was cloned by grafting scions from a tree found growing in the suburb of Majadahonda, 16 km north-west of Madrid, by researchers at the Escuela Técnica Superior de Ingenieros de Montes, Universidad Politėcnica de Madrid in 1993. The tree is one of a number found to have a very high resistance to Dutch Elm Disease, on a par with, if not greater than, the hybrid cultivar 'Sapporo Autumn Gold'. In the Madrid study, the appearance of the tree was rated 4.1 / 5.
Bacterial wilt of carnations is a bacterial disease caused by the plant pathogen Paraburkholderia caryophylli. Previously named Pseudomonas caryophilli, the pathogen is an aerobic gram negative bacteria known for only being capable of entering its host through wounds. Once inside the host, it colonizes the vascular system and roots causing symptoms such as, internal stem cracking, yellowing of the leaves, wilting, and the development of cankers. As a bacterial disease, bacterial wilt of carnations can also be characterized by signs such as bacterial streaming, and bacterial ooze.
Charles Russell Burnham (1904–1995) was an American plant geneticist who studied maize cytology and genetics. In 1968 he was elected a fellow of the American Society of Agronomy. After his retirement he played a critical role in developing a blight resistant strain of the American chestnut.
Species which are not native to a forest ecosystem can act as an agent of disturbance, changing forest dynamics as they invade and spread. Invasive insects and pathogens (diseases) are introduced to the United States through international trade, and spread through means of natural and human-dispersal. Invasive insects and pathogens are a serious threat to many forests in the United States and have decimated populations of several tree species, including American chestnut, American elm, eastern hemlock, whitebark pine, and the native ash species. The loss of these tree species is typically rapid with both short and long-term impacts to the forest ecosystem.
The Precoce Migoule is a chestnut hybrid, a natural cross between a European chestnut and a Japanese chestnut. It was discovered by J. Dufrenoy at the orchard of Migoule in Brive-la-Gaillarde. The tree is vigorous and erect growing with growth of a metre or more in a season if the conditions are right. It is a large sized chestnut tree with height reaching 20 m or more and 7.5-10 m wide. Trees start to bear after 3 to 5 years. Full nut production in 12 - 20 years depending on the location.
Marsol is a natural chestnut hybrid, a cross between a European chestnut and Japanese.
The Darling 58, also known as Darling 54, is a genetically engineered American chestnut tree. The tree was created by American Chestnut Research & Restoration Program at the State University of New York College of Environmental Science and Forestry in collaboration with The American Chestnut Foundation (TACF) to restore the American chestnut to the forests of North America. These Darling-58 trees are attacked by chestnut blight, but survive. Darling-58 trees survive to reach maturity, produce chestnuts, and multiply to restore the American chestnut tree to the forests of North America.
