Bacterial Brown Spot
Acidovorax (syn. Pseudomonas)
Bacterial Brown Spot begins as a soft, watery lesion, usually on the orchid’s leaf, that eventually turns brown. In advanced stages, the brown spot will begin to exude a foul-smelling dark liquid.This disease is most prevalent in Phalaenopsis, and is as deadly. It is especially active under wet and cool conditions.
Symptoms :- starting as a soft, water-soaked spot that later becomes brown or black. On older plants, it starts anywhere on a leaf and finally reaches the growing point. Plants may be killed.
Treatment: Immediately remove infected leaves with a sterile cutting edge. spray the plant with a bactericide. Disinfect growing area with 10% bleach solution.
prevention:- Bacteria spread from orchid to orchid by splashing water and from place to place with infected plants. Warm, moist conditions favor the disease. Avoid overhead irrigation and provide good aeration to promote drying. Keep benches clean and reasonably dry.Separate diseased and healthy plants.