Leaf sheats getting glassy (and mushy) => spreading to plants

[Lars Kurth]

Seems I managed to get myself a disease into the greenhouse in the summer, which now as the colder winter months approach is taking a bit more of a hold. As preparation for winter I only water every 5-7 days and essentially switched the hydrofogger off (it may come on for a few minutes in the morning).

I have not taken it seriously in the summer, as there did not seem to be any real spread. On two Cattleyas, the Sarongs instead of drying, suddenly got glassy and mushy. I removed the sarong carefully and that was it.

Now as a lot more plants are maturing, and on very careful inspection not only Catts, but also other plants which have fleshy leaf sheats\sarongs are affected or at least look susceptible. Examples are: some Coelogyne, Cattleya, Maxillaria, ... What is odd, is that this year all my leaf sheets\sarongs are much bigger and seem to hold a lot of water (they look really succulent). Many have grown slightly taller than the pseudobulbs and when the bulbs emerge, and the sarong opens to the top can trap water. Thus, this may be as simple as water getting trapped between the sarong and the pseudobulbs.

Anyway, as it was getting darker and I was working hard, I did not have time to check the greenhouse much. Yesterday evening, I discovered that on my Cattleya maxima the second shoot has become brown mush and tipped over in the middle. Leaf looking totally unaffected and healthy; the same is true for the roots. The middle of the bulb: mushy light brown, very watery. It looked as if whatever affected the leaf sheath has infected the freshly grown pseudobulb where it encased the bulb. Also there was a strange smell in the greenhouse.

I checked in the literature and could not find anything conclusive. According to the descriptions it could be anything from bacterial rot, to Phytium or Phytophora or even Sclerotium.

I cleaned up the affected plant and isolated it. Then drenched the greenhouse and plants with Previcur N, to ensure that the plants get some systemic protection.
The book I have recommends it against Phytophthora, Pythium and bacterial issues.

I am planning to apply Agri Foss next weekend with the watering. And of course I will remove leaf-sheats as soon as practicable without injuring pseudobulbs.

Maybe adding a bit of Physan to the water tank as recommended in another thread on the forum is also a good idea.

Has anybody had any similar experiences? Any advice?
It would also interest me why all my Sarongs are so odd this year! I will post a picture soon ...

Best Regards
Lars

[Lars Kurth]

Don't have a picture of an affected Sarong, but you can see how the Sarongs have grown larger than the pseudobulb. When the bulb comes out, the top of the Saron opens and water can get trapped between bulb and sarong.

Also when the sarongs become yellow, some do not dry but become glassy and mushy.