Gymnosporangium clavariiforme
Encyclopedia
Gymnosporangium clavariiforme is a species of rust
fungus
which alternately infects Juniper
us and hawthorns
.
In junipers,the primary hosts, G. clavariiforme produces a set of orange tentacle-like spore
tubes called telial horns
. These horns expand and have a jelly like consistency when wet. The spores are released and travel on the wind until they infect a hawthorn tree.
On the secondary hosts, the fungus produces yellowish depressions on the leaves. It also infects the fruit, which grows whitish tubes like a Medusa head. These are the spore tubes. The spores must then infect a juniper to complete the life cycle.
The fungus does not cause serious damage to junipers, but hawthorns can suffer serious loss of haw production due to the effects of the fungus.
Rust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
which alternately infects Juniper
Juniper
Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...
us and hawthorns
Crataegus
Crataegus , commonly called hawthorn or thornapple, is a large genus of shrubs and trees in the rose family, Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. The name hawthorn was originally applied to the species native to northern Europe,...
.
In junipers,the primary hosts, G. clavariiforme produces a set of orange tentacle-like spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
tubes called telial horns
Telia
Telia may refer to:*Telia - part of the reproductive cycle of Rusts*Telia Digital-tv - a Swedish TV platform*Telia, Nepal - a village in Nepal*TeliaSonera - a Swedish/Finnish telecom operator*Telia Challenge Waxholm - Golf tournament...
. These horns expand and have a jelly like consistency when wet. The spores are released and travel on the wind until they infect a hawthorn tree.
On the secondary hosts, the fungus produces yellowish depressions on the leaves. It also infects the fruit, which grows whitish tubes like a Medusa head. These are the spore tubes. The spores must then infect a juniper to complete the life cycle.
The fungus does not cause serious damage to junipers, but hawthorns can suffer serious loss of haw production due to the effects of the fungus.
Further reading
- Phillips, D. H., & Burdekin, D. A. (1992). Diseases of Forest and Ornamental Trees. Macmillan.
- Scharpf, R. F., ed. (1993). Diseases of Pacific Coast Conifers. USDA Forest Service Agricultural Handbook 521.