Orchid Diseases

 

Unfortunately, along with the pleasure of seeing your orchids come to bloom, there are a few negative aspects to orchid growing such as disorders and disease. Most orchid sicknesses are preventable by proper growing conditions. We hope you never encounter any of these.

Basal Rot
Basal rot is commonly known as 'Southern Blight'. It is directly related to watering methods and practices. Either over watering, or water left standing in the crown of plants combined with cool humid situations can bring on this condition.

Basal rot, as the name suggests, starts at the bottom or the crown of the plant and proceeds upward.  The condition is discovered on a plant with multiple growths, and only a small portion is afflicted, you can attempt to save the plant by cutting away the diseased portion with a sharp knife and treating the wound with sulphur. Keep on the dry side after the "operation" and hope the rot does not spread.

Botrytis
This is a fungal disease which affects primarily the flowers of phalaenopsis, cattleya, cymbidium and dendrobium. This condition occurs most frequently in cool, moist conditions where there is little air movement. Symptoms are tiny black spots on the petals which soon grow larger and in extreme circumstances are covered with a grey fuzzy mold. If caught early, take measures to increase night time temperatures to no less than 65 degree F and provide maximum air circulation.

Remove and destroy badly infected material such as dead flowers which have fallen to the floor and are covered with mold. Spray flooring with a strong solution of fungicide. Spray plants with a mild solution of physan or other liquid fungicide. This will not reverse the damage already manifest on your bloom, but should dry up the affected areas and halt the further spread of spores.

 

Fusarium Wilt
Not a disease in itself, but rather a common affliction due to poor culture or growing conditions. The most often contributing factor is severe shortage of water, especially during the growing season. This is evidenced by extremely shriveled, desiccated leaves. Over watering can produce the same symptoms once the roots have rotted and can no longer provide moisture to the plant.

Remedy: Pull the plant out of the pot. If there are no live roots, give it a decent burial because it will not be worth the time and effort spent to attempt a resurrection. If in the early stages however, and if there are still some viable roots present, you can attempt to save it.

Repot immediately in fresh moist orchid seedling mix. Put the newly potted plant in a more subdued light than where it was growing and keep the mix on the moist side, but not wet. Mist once or twice a day to help humidity.

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