Dibotryon morbosum
Encyclopedia
Dibotryon morbosum or Apiosporina morbosa is a plant pathogen, which is the causal agent of black knot. It affects the cherry
, plum
and apricot
trees of North America
. The disease produces rough, black areas that encircle and kill the infested parts, and provide habitat for insects.
The disease was first described in 1821 in Pennsylvania
but has spread across North America. While it was one of the most destructive diseases of the plum and cherry trees in the late 19th century, today it is relatively well controlled and only seen in poorly managed orchards or where strongly established.
Black Knot occurs only on the wood parts of trees, primarily on twigs and branches but can spread to larger limbs and even the trunk. Olive-green swellings from the disease are visible in the late spring, but as it spreads and matures typically by autumn rough black knots circle and kill affected parts. The knots vary in size from one inch to one foot (2.5 cm - 30 cm). Older knots can kill trees by promoting insect infestations.
The most common treatments are pruning infected parts during the winter and spraying buds with a fungicide
. Nearby wild plants with the disease are also destroyed.
Cherry
The cherry is the fruit of many plants of the genus Prunus, and is a fleshy stone fruit. The cherry fruits of commerce are usually obtained from a limited number of species, including especially cultivars of the wild cherry, Prunus avium....
, plum
Plum
A plum or gage is a stone fruit tree in the genus Prunus, subgenus Prunus. The subgenus is distinguished from other subgenera in the shoots having a terminal bud and solitary side buds , the flowers in groups of one to five together on short stems, and the fruit having a groove running down one...
and apricot
Apricot
The apricot, Prunus armeniaca, is a species of Prunus, classified with the plum in the subgenus Prunus. The native range is somewhat uncertain due to its extensive prehistoric cultivation.- Description :...
trees of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. The disease produces rough, black areas that encircle and kill the infested parts, and provide habitat for insects.
The disease was first described in 1821 in Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
but has spread across North America. While it was one of the most destructive diseases of the plum and cherry trees in the late 19th century, today it is relatively well controlled and only seen in poorly managed orchards or where strongly established.
Black Knot occurs only on the wood parts of trees, primarily on twigs and branches but can spread to larger limbs and even the trunk. Olive-green swellings from the disease are visible in the late spring, but as it spreads and matures typically by autumn rough black knots circle and kill affected parts. The knots vary in size from one inch to one foot (2.5 cm - 30 cm). Older knots can kill trees by promoting insect infestations.
The most common treatments are pruning infected parts during the winter and spraying buds with a fungicide
Fungicide
Fungicides are chemical compounds or biological organisms used to kill or inhibit fungi or fungal spores. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality and profit. Fungicides are used both in agriculture and to fight fungal infections in animals...
. Nearby wild plants with the disease are also destroyed.