Pythium or Phytophthora?

Pythium or Phytophthora?  Does it really make a difference?  The outcome is the same, loss of the plant.   I recently purchased three different chimera African violets from a reputable seller on e-bay.  I have purchased other plants from this grower in the past and the plants were healthy, disease free and grew well.  But since I lost about 3/4 of my collection to Pythium or Phytophthora about one and a half years ago, I have started isolating the new plants for at least 4-8 weeks from the rest of the collection to assure no issues insects or disease was spread to the collection if the  newly acquired plants were infected.  Well guess what?”  About three weeks after I unwrapped my new plants and place them in the isolation area and all seemed to be going well, I removed the flower stems for propagation (they were all flowering).  I prepared the culture tubes, sterilized the stems and set them up in the culture tubes.  Within 5 days ALL the flower stems of one of the plants (Neptune’s Thunder) were covered in a fungus.  None of my other stems were impacted and seemed fine.  Subsequently the other stems went on to form plantlets.  Now I figured no problem with Neptune’s Thunder as there will be other flower stems from this plant.  A week later I noticed some of the outer leaves were drooping.  I took a closer look.  I cut them off at the base and  observed the below.  Notice the base of the stem which is blackish/brownish in color and the area that is discolored was soft. (All images below can be enlarged by clicking on them).

Pythium or Phytophthora or some other fungus?  I do not know and what difference did it make?  Below is the plant right after I took the leaves off.  Note the circled area and the darkened stens although the plant looks like it can be saved.  I immediately treated it with a fungicide. 

The below image is the outcome just 5 days later!

Yes the plant is lost.  But I am so glad I kept these plants in isolation.  But an interesting consideration was that perhaps the reason I lost all the tissues cultures on this plant (Neptune’s Thunder)(Click on link to see image) was that systemically the plant was already infected.  The disinfection that occurred is only on the surface and not internal.   To end this month on a positive note one of three plants in this batch was a Yachiyo and continued to grow and bloom during this entire period. 

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