Search results
Results From The WOW.Com Content Network
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] If a plant is also infected with the Cymbidium mosaic virus, it can lead to a condition called blossom brown necrotic streak. [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] Symptoms of this pathogen include stunting and chlorosis. [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 ...
Symptoms of infection include a downward curling of the leaves, leaf tip dieback, stunting, necrosis of growing leaf tips, sunken 'chicken pox-like' spots on leaves (often with a surrounding halo), stem death and yellowing. [7] Since these symptoms are so generic, extreme caution must be taken when introducing new plants to your greenhouse.
Leaf spots are visible symptoms of virus infections on plants, and are referred to as systemic symptoms. [7] In systematic virus infections leaf spots caused by viruses show a loss of green colour in leaves, due to chlorosis which is a repression of chlorophyll development. [ 1 ]
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 ...
Asperisporium caricae is an ascomycete fungus that is a plant pathogen, found in North and South America. It is responsible for the black spot disease on papaya trees. It affects generally leaves and fruits at any time. Sporodochia of Asperisporium caricae was growing under side of leaf, dark blackish brown to black, stroma well-developed ...