Exobasidium dubium
| Exobasidium dubium | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Exobasidium dubium | ||||||||||||
| Raciborski |
Exobasidium dubium is a mushroom art family of Nacktbasidienverwandten (Exobasidiaceae) from the order Ustilaginomycotina . It is an endoparasite of Rhododendron yedoense var. Yedoense f. yedoense and Rhododendron luteum . Symptoms of infection by the fungus are reddish or pale spots on the leaves and the protrusion of the mycelium on the underside of the leaves of the host plants. The distribution of the species covers a Eurasian area.
features
Macroscopic features
Exobasidium dubium is initially invisible to the naked eye. Symptoms of the infestation are round, 3–12 mm large, colored spots on the upper side of the leaf and, in the late stages, the emergence of powdery mycelium on the undersides of young leaves.
Microscopic features
As with all naked basidia , the mycelium of Exobasidium dubium grows intercellularly and forms suction threads that grow into the host's storage tissue. The three- to five-pore, 20–30 × 6.5–10 µm large basidia are long, unseptate and cylindrical to club-shaped. They grow directly from the host epidermis or from stomata . The elliptical to egg-shaped spores are hyaline , 15-25 × 3.8-5 µm in size. At first they are unsepted, when ripe they have one to three, rarely six septa . The conidia are hyaline , very variable in shape and 6–14 × 1–2 μm in size.
distribution
The known distribution area of Exobasidum dubium extends over large parts of Eurasia from Europe to Japan .
ecology
The host plants of Exobasidium dubium are Rhododendron yedoense var. Yedoense f. yedoense and Rhododendron luteum . The fungus feeds on the nutrients present in the storage tissue of the plants, its basidia later break through the leaf surface and release spores. After they have fallen on a suitable substrate, these germinate via germ tubes, from which new mycelium with conidia then develops.
swell
- H. Nagao, M. Akimoto, K. Kishi, A. Ezuka, M. Kakishima: Exobasidium dubium and E. miyabei sp. nov. causing Exobasidium leaf blisters on Rhododendron spp. in Japan . In: Mycoscience . 44, No. 1, February 1, 2003, ISSN 1340-3540 , pp. 1-9. doi : 10.1007 / s10267-002-0068-x . Retrieved October 6, 2012.