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Blackspot   Phytopathology ]
Black spot disease, Black rot

Dictionary of botanic terminology - index of names

  Any of several fungous diseases of plants that produce small black spots on the leaf or stems of many plant species.  
Black-spot disease of stapeliads Phytopathology ]
  A common fungal disease which principally affects succulent Asclepiadaceae , it can cause serious damage, and plants may succumbs to it (especially seedlings)  
Black spot looks exactly what the name describes. The surface of the plant will develop blackish areas on the epidermis.  Depending on the type of rot, these spots may be either wet or dry and may extend underneath the dermal surface. Wet rots are much more serious than dry rots. One of the more common wet rots is caused by phytophthora, a fungus. If these show up, it is best to discard the plant and start over. Because this disease can be spread in contaminated soil, it is best to throw the whole pot in the trash. Donít think to recycle the potting soil it will simply spread the disease to other plants.

This diseases are due principally to inadequate cultural conditions like low winter temperature, poor ventilation, overwatering and excess of nitrogen. Plants are particularly at risk during the overwintering ( when most of the plants donít tolerate temperature under 10įC) and some species proved to be very problematic (Tavaresia spp., Hoodia spp., Larryleachia (Trichocaulon) spp.) sometimes even during the growth season.

Prevention and cultural disease control is the most important step in reducing this problem as there  is no an effective treatment, anyway when black rot is seen at an early stage it is possible to try to recover the plants removing and disposing carefully the affected parts and placing the plant in quarantine.
Reduce water applications to any plants suspected of stem rot disease and be sure to start with fresh potting medium, pots and pathogen-free cuttings for each crop.






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