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Stethopachys formosa, the orchid beetle or dendrobium beetle, is an Australian insect found in northern New South Wales, Northern Territory and Queensland. [2] They cannot survive in colder climates, and they do not appear in Southern states. [3] This insect feeds on the flowers and leaves of orchids, often causing damage to cultivated plants. [4]
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]
They point upwards, taking the form of a basket around the tall, many-noded, fusiform, canelike, yellow pseudobulbs, catching the decaying leaves and detritus upon which the plant feeds. These pseudobulbs can develop a gigantic size, up to 60 cm long. This robust orchid can grow very large, sometimes with an estimated weight over a tonne.
Tobacco mosaic virus—orchid strain 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 ]
Dendrobium gracilicaule, commonly known as the blotched cane orchid or yellow cane orchid, [2] is an epiphytic or lithophytic orchid in the family Orchidaceae. It has cylindrical pseudobulbs, between three and seven thin leaves and up to thirty often drooping, cream-coloured to yellow or greenish flowers, sometimes with reddish brown blotches on the back.
Dactylorhiza maculata subsp. fuchsii, the common spotted orchid, is a subspecies of flowering plant in the orchid family Orchidaceae. Dactylorhiza maculata subsp. fuchsii is one of Europe's most common wild orchids. It is widespread across much of Europe, with the range extending eastward into Siberia, Mongolia and Xinjiang.
Leaf spots can vary in size, shape, and color depending on the age and type of the cause or pathogen. Plants, shrubs and trees are weakened by the spots on the leaves as they reduce available foliar space for photosynthesis. Other forms of leaf spot diseases include leaf rust, downy mildew and blights. [4]
The black spots can become about 5 millimeters in diameter. [1] As the season continues, the tissue around the original spot may become necrotic. [4] In severe cases of the disease there is premature shedding of leaves, blight of young leaves and shoots, and complete defoliation early in the fall. [1] Fruits that are infected become crumpled. [1]