Multifloral rot

[Trithor]

I got back from the farm this afternoon to find a few of my (as luck would have it) best multis had developed a nasty case of rot. Affected are 2 roths, 2 m koopowitz, a gigantifoliums, a sanderianum, a philippinense, and two yang-ji apples. All the rest of my plants seem unaffected, but obviously closer inspection in the morning will be needed. The plants were distributed through the greenhouse (as in not near each other). The plants have a pale brown, to mid brown weeping aromatic infection. I have removed the plants from the greenhouse, unpotted them ( not much of note) cut away whatever infected tissue is feasible, and soaked them in Captab, and allowed them to air dry. In the morning I will dust with cinnamon (for whatever that is worth), and then I will repot and keep them isolated.

Any suggestions will be welcome, these are very special plants and form the core of my best plants (how does that happen?)

 

[Fabrice]

Did you take photos please?

With your description, probably bacterial problem.

The origin could be cooling temperatures with not enough ventilation?

 

[ehanes7612]

i agree with fabrice..happened to me too

 

[John M]

Sounds just like Erwinia infection. I am constantly inspecting my strap leafed Paphs and Phrags for this infection too. It shows up very suddenly and seemingly without any reason. I treat by promptly removing the affected tissue, even if it means the entire growth, right down to the rhizome. I spray the affected area with "No-Damp" and place the plant in a location where it gets a LOT of air movement. Usually, that means placing it on my potting bench, which is right in front of a 48" exhaust fan. If the fan is not running, I'll place the plant where it will get a good blast from the circulating fan. The next day, I will spray the entire plant with aspirin water (1 regular aspirin disolved in 1 litre of water). Most plants recover; some don't. It's disheartening. Prevention includes keeping your growing area clean, providing the best care possible (which reduces stress on the plants) and providing more air movement at all times. I know I don't have enough air movement and I intend to fix that by installing more fans....as soon as I can afford them.

Not sure if I should say this....because the "culture" here at ST has moved to be very anti-potassium (increase use of K-lite, etc.). However, I used to use a hydroponic feed most of the time (7-11-27), and it seemed to work very well for me. But, like many people, I was intrigued by the low K talk. So, I switched feeds and used ones with more moderate levels of K. Then, I began to get a LOT of this Erwinia rot...everywhere in my Paphs and Phrags. Finally, I went back to my 7-11-27 and the incidence of rot has reduced dramatically. It still happens; but, with much less frequency. Long ago, I came to understand that K helped make strong walled plant cells and that helped the plants to resist being infected by disease pathogens, like Erwinia bacteria. That's why I started using it. My experience with more rot when I stopped using it and then less rot when I went back to it has demonstrated to me that there's still more to learn about the benefits and drawbacks of a low K formula. I did notice that with less K, many plants had a growth spurt; but, what good is that if they are so soft that they get infected and rot?

I have also noted over the decades of growing that low calcium seems to invite bacterial infection. I've had plants that were cured of rot simply by watering them with Phostrogen, which is a high calcium fertilizer from the U.K.

 

[Chicago Chad]

Sorry for the loss Trithor. Hopefully you can salvage your special plants.
Thanks for feedback John. I have seen some issues with plant tissue in a few paphs this year after switching to Klite, but I have not concluded that the fertilizer is the issue. You do make a good case with things to consider.

 

[Rick]

I'd agree it sounds like Erwinia, and I use appropriate surgery, cinnomen and Dragons Blood to work it over.

However, there's research (and several personal accounts) that plants with inversed K and Ca tissue concentrations (i.e. more K than Ca) are more susceptable to erwinia. Cell wall integrity is due to Ca (not K), but unfortunatly once a plant makes a leaf under whatever mineral regime its immediately exposed to will determine its tissue content (a mature leaf cannot correct).

Since orchids and other epiphytes are extremely efficient at picking up K, even "moderate use" of K as John mentioned will not stop orchids from sucking up excess K and reducing leaf tissue concentrations of Ca and Mg.

Talking to a plant pathologist, I was told that erwinia is cued in to growth hormones and the lysing compounds at the base of leaves. When the plant goes into growth of new roots or shoots, and old leaves are lysed off, the erwinia is cued in to the digesting site. If cell integrity is poor, then the infection can easily spread outside of the lysing area.

In comparison to John, and the longest user of a true low K feeding regime, my incidence of erwinia is has been greatly reduced over the last 2 years, and the handful of plants that show it are often able to get over it with no treatment at all.

The worst cases I still see are new plants that are still full of high K leaves.

 

[emydura]

It seems extraordinary you would get so many cases of rot at the same time. Has anything in particular triggered this? Had you just watered? Did you get a cold spell. Did the heating stop working?

All the treatment in the world isn't going to help if you can't determine what the cause of the rot is. Otherwise the plants will rot again including your healthy ones. We all get rot from time to time but it is unusual that so many healthy plants rotted at the identical time. It sounds like a specific event has caused this rather than ongoing cultural issues such as a lack of Ca or K.

 

[John M]

Thanks Rick. 'Still trying to understand this. I have noticed that Calcium plays a roll in reduced incidence of rot. But, why then when I reduced my K; but, kept my C the same, did I see more rot? It's maddening to see a gorgeous, perfectly healthy looking (expensive!!!) plant suddenly become consumed by Erwinia. It's upset me so many times. I've sometimes considered getting out of growing because of the disappointments. It's always the most valuable or my favourite plants that seem to be hit. I'd LOVE, LOVE, LOVE to figure out how to stop this problem.

 

[Rick]

http://www.fluidfertilizer.com/pastart/pdf/36p16-19.pdf

Noting that the above is beans and not multifloral paphs, the physiology of tissue Ca is the same for bean plants and orchids.

tissue Ca is always inversely related to tissue K, and K always is selectively inducted unless in very low supply (not based on ratio of K and Ca in environment).

 

[John M]

http://www.fluidfertilizer.com/pastart/pdf/36p16-19.pdf
tissue Ca is always inversely related to tissue K, and K always is selectively inducted unless in very low supply (not based on ratio of K and Ca in environment).

Thanks! Now, can you say that in English, please?

 

[orcoholic]

I've rotted some too. If you can save the plants they should begin to grow more divisions from the base. I rotted a roths and now it has five new fans growing from the base. Don't give up. It takes a bit of time for them to start, but as long as the plant isn't dead they should grow.

THere was a thread by Hardy where he actually removed the center growth and thus stimulated the growths at the base of the stump that was left after he removed the center growth. The same thing happens to Catts, Phals and a lot of other orchids that have active eyes at their base.

 

[Rick]

I have also noted over the decades of growing that low calcium seems to invite bacterial infection. I've had plants that were cured of rot simply by watering them with Phostrogen, which is a high calcium fertilizer from the U.K.

SlipperKing and myself used to dump bonemeal (calcium phosphate) on active infections with some success.

I would only give that action 50/50, but SK Rick said he would see better results.

 

[Rick]

Thanks! Now, can you say that in English, please?

The ratio of Ca to K is irrelevant since the plant finds and picks up any K no matter how little K is in the environment and no matter how much Ca is in the environment.

Since K is actually rare in the environment (relative to Ca) plants have active uptake mechanisms for K (that will block Ca uptake) to take advantage of high pulses of K.

The agri litterature is pretty well maxed out on this phenomena.

There was a study done by Cornell on orchids too in the mid 1970's (Stone posted the orirginal link, but I graphed the results and reposted recently). Even with 200ppm of soluble Ca available, orchids selectively increased tissue K when fert concentrations were lower than 200ppm. Even at 50ppm K and 200ppm Ca, Cattleya leaves had more K than Ca in their tissues, which is backwards for most wild orchids.

In order to get more Ca into a plant cell, you need to get K down to environmentally relevant concentrations of < 5 or so ppm. I've cut back my K exposure to less than 2-3 ppm for months on end with great results.

I have lots of non orchid house plants that grow great on my well water which has non detectable (less than 2ppm) of K.

 

[Rick]

But, why then when I reduced my K; but, kept my C the same, did I see more rot?

Well a small reduction doesn't work for a start. Secondly once a plant is stuffed full of K, I really haven't found anything to reduce it in the leaves/growths already produced.

I don't think your short term reduction in K precipitated rots, but untill you get all new leaves, roots and growths made with high Ca content, the plants are just as susceptable to rot.

I'm still not ruling out the posibility that in a true low K system, that immediate uptake of increased Ca for a plant with good root system could possibly help build a plants immediate immune system, and subsquently reduce rots in plants with high tissue K. But I'm saying that because several of us experienced reduce infection rates in the first year of going low K.

 

[Rick]

I also think phosphate has something to say in this mess.

It takes energy to run a metabolism, and ATP is the currency of all this. So I'd be concerned about P deficiency if Ca is relentlessly increased to compensate for K issues.

 

[SlipperFan]

My experience is different from John's. I was having a terrible time with erwina, especially in my Phrags. Since I switched to K-lite, i've seen a gradual, but significant, decrease in erwina. I still get it occasionally, but nothing like I used to.

 

[John M]

Thanks Rick. Lots to think about......

 

[Rick]

Thanks Rick. Lots to think about......

You're welcome John.

Here's another thing to add to the pile to think about. The amount of K sequestered and stored in the potting mix can be considerable (check out Xaviers recent thread on different mixes and K http://www.slippertalk.com/forum/showthread.php?t=31056 it also has those Cornell graphs I was talking about pgs 3 & 4).

So even if you cut back on K in the feed, there's still plenty sunk into old mix. So if you don't repot to fresh mix at the same time as going low K, you probably aren't going low K in real life for several months (if at all).

At the time I went to low K, I had already gone into a big program to move most of my Paphs and Phrags into baskets (starting about 6 months prior), and I accelerated that program, and general repotting, after going low K.

Another anecdote, I purchased a couple of dalasandroi seedlings from FV early/mid last summer. Before repotting, and within a month both succumbed to erwinia. It was a very hot summer, and even with all the GH controls in place, I was still hitting about 88- 90F. So blamed the erwinia on excess heat. Tom very graciously replaced the plants from the same batch, within that first month or so. This time I repotted to baskets. Those replacements are not only still alive, but have at least doubled in size after a year. I've even bumped them off the bench to the floor a couple times breaking leaves, and not a hint of erwinia.

 

[mrhappyrotter]

If it's Erwinia, I feel for you. I had a really severe outbreak of it about 10 years ago, and I am still extremely regretful about the plants I lost to it. I lost many of my treasured paphs and phrags to it. It makes me sad to even think about the lost plants. The rot didn't kill many plants outright, it was the after shock where I failed.

My problem was that I was too busy at the time, didn't notice it until it was too late, and then I had a really hard time recovering the infected plants. That stuff moves extremely quickly, and I wasn't experienced enough at the time to nurse my sick plants back to health.

I have a few phrags with caudatum-type backgrounds that periodically seem to be susceptible. Fortunately I have been able to catch it in time. I always remove the infected leaves, and I've been successful with cinnamon treatment. I still don't know why it strikes. I don't fertilize particularly heavily, I watch the caudatum group and hybrids like a hawk, and I have really good airflow via big fans. And yet, it seems to strike randomly.

Since the big outbreak, though, I've not had any issues with paphs and erwinia. Hopefully the advice in this thread will help.

 

[naoki]

Gary, do you think aspirin might be helpful? It is well known that SA is important for plants disease (and stress) resistance. I wasn't sure if ASA (aspirin) has the similar effect, so I looked up a little more today. There are quite a few experiments showing externally applied ASA (aspirin) can have similar effects:

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.1992.tb00133.x/abstract
http://www.cabdirect.org/abstracts/20123408761.html
http://link.springer.com/article/10.1023/A:1006386800974

Originally, it was resistance against TMV, but we now know the same defense pathway is used for fungal and bacterial infection.

I've started to folliar spray/drench with aspirin water this year. I can't say if I see any effects, but I haven't killed may plants this year. Did other people with more experiences try this and decide that it doesn't work with orchids? Obviously, it won't be enough by itself once the plants are already infected. But it may help a little bit.