Rapidly yellowing leaves (pests?) on well-established phal

[journorchid]

I have a well-established phal that until recently was in beautiful spike. I had had earlier mealybug problems but thought I had them licked. Then the blooms on one part of the bifurcated spike wilted quite rapidly. I assumed it was genetics, and that I had just purchased (from a very reputable grower) a fast (1-2-week wilter). Then this weekend I discovered two things:

1. The wilt area was totally consumed with mealybugs and scale. I hadn't noticed them because the mbugs were hiding on the blossoms, which are white, and I had never had scale before so never knew exactly how to keep an eye out. (I ended up just chopping off that half of the spike b/c there are no pests on the other half and I didn't want to risk further infestation.)

2. Most importantly, the bottom leaf on one side had turned totally yellow and very floppy seemingly overnight. I mean, it went from healthy to deader than a doornail. Since I am new to this, I imagined this might be a normal leaf dying situation, so I just left it there until it was floppy like overcooked pasta, then decided (based on scale-sucking suspicions) to cut it off and brush the cut point with physan. Now, to my horror, the next leaf up is doing exactly the same thing: Yellowing overnight, to the point of unsalvageable.

What the heck is this, and will it spread? I have been spraying the plant with a weak solution of physan and even included a couple of drops when I did a dunk-watering over the weekend.

Since the blooms, spike, and four reamaining leaves seem to be quite perky and fine (tho with a bit of splitting and browing at the tips) and I have decent root growth, I am assuming this yellowing deal is pest-related. Do I need an urgent repot? Sad to do when the baby is in spike like this, but I don't want to lose the plant.

I know my posts here might indicate that I have a special talent for killing orchids, but I can report that my onc. is doing OK despite earlier predictions, and that the really problematic onces (including one you'll see later today) were all big-box clearance rescues that were in poor shape when I got them. The one I'm writing on today is a different story -- a big, old plant grown by a real local nursury.

The problem is spreading so fast -- please help before it is too late.

Orchid love and many thanks,

Dan

[janet_a]

yellowing overnight is usually an indication of stem rot (aka crown rot). yank it out of the pot NOW and clean off all the media--if you have any black sticky gunk down there (or if the rootball simply falls off), you have two options: toss the plant, pot and all, or try and salvage it. buy a few bottles of H2O2 and prepare to dunk the plant in it several times over the next few weeks. gimme a sec...

http://www.firstrays.com/remedies.htm

see treatment for crown rot; works elsewhere on the plant too.

whatever you do, DON'T handle any other plants until you've thoroughly washed your hands--rot spreads easily.

[mayres]

Yes, I have seen mealy bugs kill off a leaf on a phal seemingly overnight too. I have not examined them closely, but have read that they can be under the media sucking at the roots too (?). I recently had mealies on a phal and had a similar experience, except that believe it or not they sucked the life out of a leaf in the middle of other leaves - leaving it yellow/brown in just a couple days. A systemic may be warranted - such as Bayer Rose and Flower spray. You have to stay with the program too - just when you think you have the problem licked they will spring up again. I think you are onto the problem - just have to stick with it with vigilence.

Physan is for fungus. It is not an insecticide. As Mayres says, you need a systemic like Bayer Rose and Flower Spray. It will literally get into all parts of the plant and will kill the bugs from root tips to leaf tips. Use it once a week for three weeks. I would treat all your plants. Then keep a vigilant eye on them as this pest spreads like wildfire. It sounds like you need this spray in a hurry.

[journorchid]

Thanks for all the input on this urgent matter.

Crown Rot inspection: All of the roots coming directly off the bottom of the stem appear rotted, but the aerial and side roots are generally healthy. Dunno if this is normal rot (never seen a phal without at least some rotted roots) or the dreaded stem rot.

And yes -- my mistake on the physan. Fungicide/bactericide/virucide does not equal pesticide.

So what's the verdict: Crown rot or buggies? If crown rot, I'd think the Physan would be doing the job. (I also have another fungicide -- Daconil -- not sure if this is indicated for orchids.)

For bugs -- easy to imagine they're deep in the medium; the plant doesn't appear to have been repotted for a long time. The Bayer stuff sounds easy enough. The thing I want to avoid is repotting this plant unnecessarily when it has a couple of thriving tap roots deep in the medium and a really great spray of flowers showing. But I'd rather save the plant and lose the flowers, obviously.

Any spare thoughts and nondenominational prayers are entirely welcome. If I can't save this plant, I'm ready to give up entirely. It was doing so WELL. Grr.

Thanks, all, and please do reply with opinions on CR/bugs and which fungicide... or whether it would be bad to do a fungicide/pesticide course simultaenously.

...or, finally, if my best bet is to call the beautiful spray cut flowers and repot the dear. (This could give me the opportunity to try new media, which wouldn't be a bad thing...)

If you do advise repot, please share some advice beyond the firstrays, in particular: what to soak and/or prune to eliminate rot.

Orchid love,

Dan

[mayres]

Dan -
There is no such thing as "normal" rot! If your plant is properly taken care of you should expect NO rotten rots. If you want to truly salvage this plant I would take it out of the pot and clean up the root system - remove all black, mushy, fibrous stringy roots and leave all plump tan/green/grey fleshy ones. Put in fresh media. Spray with Bayer Rose and flower spray or something similar to get the systemic going in the plant and cut off at the pass any new crop of mealies that might be thinking of making a secondary attack! I know everyone grows orchids for the flowers, but if your plant is really suffering you might consider taking off the remaining flower spike(s) to let the plant put all its energy into rebuilding. My two cents worth - others may feel differently. mike

[janet_a]

definitely repot. toss all the old medium and disinfect the pot if you're going to reuse it.

and don't worry, i end up repotting phals in bloom all the time. doesn't seem to bother them; just try not to break the spike. (it's time like those when you wish you had a third hand. )

oh and i agree about cutting off the spike if the plant's really sickly.

[Cynthia, Prescott, AZ]

I would use Bayer Advance Tree & Shrub at 2 T per gal. I have seen it recommended at 1 t per gal, and this may work too. I just did my entire GH with close to the 2T per gal, so will report later on the effects if bad. You want to use the concentrate, because you will be using a lot to soak the pot and the mix, the most effective way to get at the mealies living in the mix and sucking on the roots, if an open mix like bark. B A Rose & Flower ready mix is too expensive, and has a synthetic pyrethrin in it that some orchids don't like.

Crown rot is not root rot. If the innner most leaf is not rotted down to it base in the plant, you do not have crown rot, and things should be easier to deal with. If you have any live roots, a repot with these just under the mix, but near the surface, so they are dryer than normal, should work.

Physan 20 is not systemic, and will not penitrate any part of the plant to kill rot, but will clean up the exterior to a great degree to avoid further rotting. It must be used carfully, as an over dose is very bad for the plant, and a lowered concentration may be better. Phyton 27 is a systemic fungicide/bacteriocide, and is well worth having around and used sparingly, as it is very expensive.

If you repot and find some live roots in the pot as well as the living airial roots, I would not remove the spike, if there are at least 2 or 3 good and large leaves. These can handle the spike. Many fungicides are very specific to particular fungi, and may not hit your particular fungus. Don't know about mixing the physan with BA products, but I would consider the BA products more important. A good watering schedule will take care of further root rot.

A certain number of dead roots in a pot are normal, at least for me, as I believe there is a limited life span of the roots.

[Lucinda Brown]

I've said this before in other posts but I'd like to help.Try Ortho systemic spray with acephate. Safe for all my orchids,I have a very varied collection,and used it on many different varieties,never harmed any. GOOD STUFF! It is systemic which means the plant will absorb it through the leaves even roots if you add a little to your water when you water it.I would spray and water some into your muchly plagued plant to give it a better chance to fight back. Home Depot or Lowe's,even your local garden center usually carries this. Good luck!

[journorchid]

OK, thanks to all, I have untertaken a repot and have used a weak soln of systemic. My choice: Ortho systemic with acephate. I gave the other plants in the collection a quick shot of it as well, just to try to clean the whole collection. The (second) yellow leaf fell off on its own accord during repot, but I have four good leaves and a number of healthy-looking roots -- not as many as I'd like for a plant of this size (leaves 7" long) but enough to think that if we kick fungus and bugs we should be good through the end of spike and dormancy.

Now: There have been two parallel conversations here, one about rot and one about insects, with no clear answer about which caused the rapid yellowing. The repot was a good thing anyway, since the medium was almost soil-like in its compaction and the roots probably wanted more airflow...

But what about the fungus amongus. Y'all know I've been using physan. And I'm sure the repot/cleaning helped. It was, as always, a delight to have Cynthia weigh in, and to correct the misimpressioin re: crown rot/other rot. (I don't have crown rot.) Don't want to ignore the fungus issue. Should I stick with Physan regimen (misting every day or two) in the places where I think the problem was starting -- e.g. where the leaves meet the stem?

Thanks again to all. You make my (orchid) life worth living.

Dan

[janet_a]

oh, if it was some kind of rot, you'd see it. if you have fresh medium, and more airflow around the roots, any fungus problem may have been solved.

[Cynthia, Prescott, AZ]

I would not worry about fungus on leaves. Fungus in the root area because of too wet or rotted mix is a concern, but you appear to be past that now. On the leaves, fungus is only a problem if your culture is bad, like too cold for the plant, or misting late in the day. I would definitely stop the frequent use of Physan. It is not totally free of consequences if you use too much or too often. Better to just use it occasionally and a lower than the recommended strength. I have a bunch of white spots on a lot of plants because I got too cavalier about measuring it by the chug-a-lug method, and no doubt got the concentration higher than recommended. Bacteria is the cause of wet rot on/in the leaves, not fungus, and culture again is what to watch out for.