''Botryosphaeria stevensii'' (''Apple sphaeropsis'') is a fungal

plant pathogen Plant diseases are diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like orga ...

that causes

canker A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticultur ...

s on several tree species including

apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

and

juniper Junipers are coniferous trees and shrubs in the genus ''Juniperus'' ( ) of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere as far south ...

as well as causing cankers on

grape A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters. The cultivation of grapes began approximately 8,0 ...

vines. It causes branch dieback, possibly affecting a large portion of the tree canopy, and if severe it can kill entire plants. It was originally found on fallen fruit of ''

Malus pumila An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are cultivated worldwide. The tree originated in Central A ...

'' in Great Britain and published and described by

Berk Berk may refer to: * Berk (name), a surname, given name, or any of several people with that name * Berk, Bolu, Turkey, a village * Berk Trade and Business School, New York City * Berk, a fictional island in the ''How to Train Your Dragon'' seri ...

as ''Sphaeropsis malorum'' in 1836 . With the epithet 'malorum' derived from the Latin for Apple. It is first seen as multiple very small, black pimples or pustules under the fruit skin before they break through the covering. Then a black conical protuberance appears, which is the spore-case of the fungus. Then a cluster of pale spores appears, on a short stem or pedicel. Later they turn black or black/brown and break off the pedicels. The spores then leave the spore-case by a small aperture at the top of the case. Infections can occur in winter or spring in the US.New York (State). Legislature. Assembly Its anamorph was revealed to be ''Diplodia mutila''. It has been found on Rocky Mountain juniper (''

Juniperus scopulorum ''Juniperus scopulorum'', the Rocky Mountain juniper, is a species of juniper native to western North America, from southwest Canada to the Great Plains of the United States and small areas of northern Mexico. They are the most widespread of all ...

'') in windbreak and ornamental plantings in the US. Multiple, coalescing cankers resulted in branch dieback and sometimes tree mortality. The fungus also was pathogenic to and caused canker formation on eastern redcedar (''

Juniperus virginiana ''Juniperus virginiana'', also known as eastern redcedar, red cedar, Virginian juniper, eastern juniper, red juniper, and other local names, is a species of juniper native to eastern North America from southeastern Canada to the Gulf of Mexico an ...

'') and Chinese juniper (''

Juniperus chinensis ''Juniperus chinensis'', the Chinese juniper, is a species of plant in the cypress family Cupressaceae, native to China, Myanmar, Japan, Korea and the Russian Far East. Growing tall, it is a very variable coniferous evergreen tree or shrub. ...

'') Prevention efforts may include careful selection of plants, including resistant

cultivars A cultivar is a kind of cultivated plant that people have selected for desired traits and which retains those traits when propagated. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue cult ...

, planting in well-draining loose soils, exposure to light and plant spacing to reduce moisture retention.

References

External links

USDA ARS Fungal Database
{{Taxonbar, from=Q10433846 Fungal plant pathogens and diseases Apple tree diseases Grapevine trunk diseases stevensii Fungi described in 1964 Fungus species