Exobasidium vexans
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Exobasidium vexans on tea leaves |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
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| Massee |
Exobasidium vexans is a smut fungus art from the family of Nacktbasidienverwandten (Exobasidiaceae). It lives as an endoparasite on tea ( Camellia sinensis ). Symptoms of the fungus infestation are red, severely swollen leaf galls that eventually burst. The species can be found everywhere in Southeast Asia, where tea also grows.
features
Macroscopic features
Exobasidium vexans is initially invisible to the naked eye. The initial symptoms of the infestation can be seen on the leaves: the leaves of infected tea plants form red spots, then several red blisters. Later, the chalk-white mycelium of the fungus breaks through and overgrows the vesicles, which soon rupture.
Microscopic features
The mycelium of Exobasidium vexans grows intercellularly and forms suction threads that grow into the host's storage tissue. The four- to five-pore, 30–35 × 5–6 µm large basidia are long, unseptate and narrow- lobed . The elliptical spores are hyaline , 13–27 × 4.5–6.5 µm in size and have thin walls. At first they are unsepted, when ripe they have a septum .
distribution
The species range of Exobasidum vexans coincides with that of tea and covers large parts of Southeast Asia . The species has not yet been found in Africa, where tea is also grown.
ecology
Exobasidium vexans only affects young leaves of the tea plant. The fungus feeds on the nutrients present in the storage tissue of the plants, its basidia later break through the stomata on the underside of the leaf and release spores. The fungus is considered to be one of the most important diseases of tea and the plantation economy and therefore a pest.
swell
- C. Booth: Exobasidium vexans. In: CMI Descriptions of Pathogenic Fungi and Bacteria 779, 1983.
