Treating my First Sick Plant

December 31, 2011 in Orchid Notes & Culture by Masood Raja

Rest in Peace: C. eldorado fantasia ‘Rafaela’ x flamea orlata

Update (Apr 30, 2012)

I have now declared this plant dead. The plant had attempted a new growth but my carelessness in watering it killed it. This means that the plant had recovered from its ailment but died because of my faulty culture practice. Sigh!

Update (Mar 13, 2012)

The plant is still alive and while there are no signs of new growths etc, the condition of the plant seems stable.

Update (Feb 20, 2012)

Well, after I was sure I had lost this plant, the plant, it seems, has surprised me. So far there is no sign of any further deterioration. The remaining one leaf and a leafless psuedobulb are doing fine and it looks like there is some root development as well. So, I hope the worst is over and looks like this plant will eventually make it.

Update (Jan 29, 2012)

I think this plant is almost dead. Lost the new growth and am left with just one leaf. Not much of root left either. I will still keep it under observation but it seems likely that all my efforts have failed. I’ll be more careful in dividing the plants in the future.

Update (Jan 18, 2012)

One more leaf started turning yellow. I cut as much of the rhizome as I safely could, drenched the plant in Physan 20 and repotted it. Looks like I am eventually going to lose this plant as there is only one old leaf and one new growth left. Since the plant has only a few roots left I planted it in a two inch pot in Sphagnum moss to encourage root growth. Will provide more details later.

Update (Jan 5, 2012):

This might still be a hasty conclusion but the plant is doing fine and I have not noticed any yellowing of the old leaves or psuedobulbs yet. I hope my extreme measures have worked. I will still keep my fingers crossed.

———————-

After the third back psuedobulb on my C. Eldorado died, I was sure that there was something wrong with this particular plant. A detailed research pointed to the most lethal diseases of all: Psuedobulb Rot or Fusarium Wilt (My guess is Fusarium Wilt).

As the symptoms did not show in the bulb part first but rather started with the yellowing of old leaves and as I had my C. eldorados on their winter dry period so water, on cold nights, could have not caused it either. This led me to believe that it was not psuedobulb rot. I think something went wrong when I repotted this plant: I either did not disinfect enough or used fungus-ridden medium, which means that it is a possible case of Fusarium Wilt.

Fusarium Wilt

Symptoms: Fusarium cana infect a plant through orchid roots or by invading the rhizome of recently divided plants. Fusarium blocks the flow of moisture through the plant’s vascular system plugging the phloem. The pathogen is spread through improper hygiene, generally as a result of using nonsterile cutting tools, which transfers the fungus from plant to plant. Infected leaves are yellow, thin, shriveled, wrinkled or wilted and eventually die. Severely infected plants may die in 3-9 weeks, while mildly infected plants gradually decline over a year or so.
The diagnostic symptom in the plant is a circle or band of purple or pinkish-purple discoloration on the outer layers of the rhizome evident when the rhizome is cut. If the disease is extensive, the entire rhizome may turn purple, and the discoloration may extend to the pseudobulbs.

Treatment: Discard infected part of rhizome and pseudobulb if the purple band is evident. Repot only the part of plant showing no purple discoloration. Drench sanitized plants in a thiophanate methyl (like Cleary’s 3336 or Banrot) following label instructions. Be diligent in disinfecting growing area and cutting tools. Each time the cutting tool contacts infected tissue, it should be sterilized before making a second cut.

Prevention: Prevention is a simple matter of following proper hygiene. Sterilize cutting tools after each use, preferably through flame sterilization.(Source)

So as a last resort, I took the plant out of the pot. The roots were intact but smelled stale like fungus. I took off the dead psuedobulbs with a heat sterilized pair of scissors and then immersed the roots in a cup of Physan 20 solution. I also drenched the new medium and the new pot in Physan 20.

As an extra, and extreme, measure I also ran some Paysan solution water through the potted plant.

I am now keeping the plant separate from other plants. So far it has not shown any new symptoms of any more yellowing of leaves etc. I will report the progress in a few weeks and keep my fingers crossed.

Meanwhile, I will welcome any suggestions.