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Odontoglossum ringspot virus (ORSV) is a plant pathogenic virus that belongs to the family Virgaviridae. It is one of the most common viruses affecting cultivated orchids, perhaps second only to the Cymbidium mosaic virus. [1] It causes spots on leaves and colored streaks on flowers. [1]
Black rot on orchids is caused by Pythium and Phytophthora species. [1] Black rot targets a variety of orchids but Cattleya orchids are especially susceptible. [1] Pythium ultimum and Phytophthora cactorum are known to cause black rot in orchids. [1] Pythium ultimum is a pathogen that causes damping-off and root rot on plants. [2]
Orchid fleck dichorhavirus, commonly called Orchid fleck virus (OFV), is a non-enveloped, segmented, single-stranded (ss) RNA negative-strand virus, transmitted by the false spider mite, Brevipalpus californicus. OFV causes necrotic and chlorotic lesions on the leaves [1] of many genera in the family Orchidaceae.
The virus has not often been reported in wild orchid populations. [2] It can be found in a wide variety of orchid genera [3] but does not infect plants other than orchids. [2] Once an orchid is infected, the virus spreads throughout the infected plant in a number of weeks. [4] Control measures may include sanitizing pruning equipment between ...
Outside of the "maculata group", D. majalis is very similar to D. maculata subsp. fuchsii, but is distinguished by the following characters: the spots of the leaves are less elongated, the bracts of the inflorescence are longer and the lower transcend the inflorescence itself; it tends to be less cylindrical (a little more 'globular'), the stem ...
The leaves are oblong or oval-lanceolate, with dark ellipsoid-shaped spots on the surface (hence the species name). The leaves are amplexicaul and can be either radical (basal) or cauline. The underground part of the stem has two webbed tubers, each deeply divided into several lobes or tubercles (characteristic of the genus Dactylorhiza ).
Dendrobium is a genus of mostly epiphytic and lithophytic orchids in the family Orchidaceae. It is a very large genus, containing more than 1,800 species that are found in diverse habitats throughout much of south, east and southeast Asia, including China, Japan, India, the Philippines, Indonesia, Australia, New Guinea, Vietnam and many of the islands of the Pacific.
Most slipper orchids have an elongate erect stem, with leaves growing along its length. But the mocassin flower or pink lady's slipper (Cypripedium acaule) has a short underground stem with leaves springing from the soil. The often hairy leaves can vary from ovate to elliptic or lanceolate, folded along their length.