Orchid rust: Uredooncidii

Synonym: Hemileia oncidii

The sexual spore organ (O) and the rust spore organ (I) are unknown, and the summer spore pile (11) is planted on the back of the leaf to form an exposed dark orange powdery summer spore plaque, while the teliospore pile (dish) is not described.

(1) harm: this rust was first found in France and later in Brazil, South America and the United States. Its harm includes: Epidendrum vitelliunum, Lycaste skinneri, Odontoqlossum hictoniensis,Oncldtum btcallosum,O.cavendtshianum,O.ceholleta,oforhesii,O.lanceanum,O. Pustllum,O.Splendidum,O.vartcosum.

(2) symptoms: like many other rust diseases, the spore pile occurs in the nearly round spot on the back of the leaf, containing orange summer spores. With the passage of time, the spot becomes brown and necrotic, and then the central part of the spot dies and turns brown. But it continues to develop, and its edges remain active and orange.

(3) Prevention and control methods: all diseased forests should be destroyed, all orchids, especially susceptible species, should be sprayed with thiram, and constantly observe the occurrence of rust.

Liu Zhongjian