BACTERIAL BROWN SPOT: On Phalaenopsis

by Robert M. [Bert] Hamilton (Compiler)

Originally published in The Orchid Doctor in 1980 and 1988

Posted by Sys Admin almost 8 years ago.

Soft water-soaked lesion; turns black or brown; spray with Physan 20, 1/2 ttpg.; repeat as needed. A66-403; A73-888; AH19

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Bacterial Infection	Comments
BACTERIAL BROWN ROT: Caused by Erwinia Cypripedii Small oval water-soaked spots in paphiopedilum leaves; change from light brown to deep chestnut enlarging steadily; can be suppressed by submerging in Natriphene at 1:2000 for 1 to 2.5 hours. BU49; OR77-166	0
BACTERIAL BROWN SPOT: Phytomonas Cattleyae Attacks cattleyas, and especially phalaenopsis and seedlings; small water-soaked spots; dirty green at first turn brown or black, enlarge rapidly; on phalaenopsis spot is blister-like and spreads rapidly to heart of plant and is fatal; cut out parts; soak community pots and plants for several hours in Natriphene or Anti-Damp; dry them out, spray with fungicide. BU47; N320	0
BACTERIAL BULB ROT: Erwinia Carotovora Found on cymbidiums; spots become soft, oozy, foul-smelling; cut off and destroy; spray other bulbs with Agri-Strep or similar with care. S205	0
BACTERIAL BULB ROT: Severe Damage to Valuable Cattleya, How to Save? Assuming roots are good, just cultivate well and a new eye will break. A73-816 (illus.); A79-785	0
BACTERIAL BULB ROT: Syringing Plants It's the best way to spread disease. A78-998 see also Brown rot; Brown spot; Miltonia scorch; Necrotic spots; Phalaenopsis (clear translucent spots); Soft rot	0
BACTERIAL DISEASES: Unusual Causes May include such factors as excremental deposits from birds (outeide), insects, rodents, lizards, etc., on leaves or in pots; for general sanitation use Physan occasionally. A80-1368; OBIV-267	0
BACTERIAL INFECTION: Phalaenopsis Leaves Yellowed, Shrivelled a Bit and Fell Off If phalaenopsis are grown too cold they are susceptible to bacterial infections; keep night temperatures at 66 to 68 degrees F. A69-242	0
BACTERIAL LEAF ROT: Erwinia Chrysanthemi a Bacillus In Hawaii; leaf rot in various orchids; water-soaked and yellow spots; preventive spray of Natriphene before wet weather and during recommended. N321	0
BACTERIAL LEAF ROT: On Leaves of Ascocendas Bordeaux mix not very effective against bacteria; try Physan at 15 ml. per gallon of water. A74-792	0
BACTERIAL LEAF SPOT: Control Basic copper sulfate (a fixed copper fungicide) at 1/2 ttpg. as spray recommended; or, Natriphene 1:2000 as drench. P71(2)24Formaldehyde 10% solution is very effective when applied solely to affected area; kills all tissue. P71(2)24	0
BACTERIAL ROT: Control Recommended Agri-mycin at about one-fifth the recommended dosage; spray no more than four times a year; if used more often it may cause deformities in flowers; use any time as pot treatment. OD73-139	0
BACTERIAL ROT: Treatment Rots caused by Pseudomonas can only be limited or arrested by a full dip in a bactericide such as Physan 20, at 15 ml. to 4 liters of water (3tpg.), a teaspoon is 5ml.; cut out diseased parts before drenching or soaking; spraying will not totally cure the problem. AU82-251	0
BACTERIAL SOFT ROT: Erwinia Carotovora, a Bacillus Incurable; rare; destructive; cattleyas most affected; destroy immediately rather than trying to heal; water-soaked green spots on leaf break open at slight touch; exudation contaminates the bench and area; foul smelling; destroy plant; drench bench, floor, etc., with mercuric chloride 1:1000; spray area with fungicide. N320+; OR74-234	0
BACTERICIDES: Recommended An effective one is Physan 20. A76-698 Recommended for orchids = Natriphene, Physan, tetracyclines, Polymixin B (Amphotericin). OD67-50 In Florida the only one officially named for use on orchids is Natriphene 97%. A86-1031	0

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