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Yellowing stems and white dots on leaves

Posted by ntran (My Page) on
Thu, Sep 6, 07 at 18:03

Hi everyone,

I've had this Phalaenopsis orchid for almost two years. It's bloomed about 3 or 4 times.

Recently the flowers have wilted and fallen off and the tips of the spike and secondary stem (I think that's what it's called) have started to turn yellow. Should I be concerned about this?

I am also concerned about these white dots on two of the leaves. They have been there for a few months... They appeared after I repotted the plant. I was going to ask about it, but then the plant started to rebloom. What are these things? Was that reblooming just a last hurrah before the plant's demise?

I've posted some pictures here:

Thanks to anyone who can help...

Follow-Up Postings:

RE: Yellowing stems and white dots on leaves

Can you get a sharper shot of the spots? Might be scale.

Meanwhile, it is perfectly normal for the flower stem to eventually die off.


RE: Yellowing stems and white dots on leaves

It looks like it might be boisduval scale or, as I call them, hell bugs. If they rub off, that's probably what you've got. If not, it could be scarring.

If it's scale, I'd rub off what you could see, take the plant out of the media, sterilize the pot, soak the plant in sudsy water and give a mist or two or three of alcohol. And keep it away from any other plants you might have.

As Cj said, don't worry about the yellowing, that's normal. You can also cut off the spike or 'secondary stem'.

RE: Yellowing stems and white dots on leaves

Thanks for replying!

Here is a close-up:

You'll also notice that there are green dots on the leaves.

I tried wiping off the white spots, but they didn't come off. They feel rough and hard. If it's from scarring then how did it get scarred in the first place? It usually gets a decent amount of indirect light (never direct) and I water it about once a week. I also try to get rid of any excess water from the bottom of the pot.

RE: Yellowing stems and white dots on leaves

Here's the detailed pic, so that no one has to cut/paste.

It looks like the white is on raised green bumps, in some cases, so I'm leaning towards scarring. Scarring can happen with any mechanical damage like cat teeth, being dropped (although the landing is the problem), or scratched. Insects can also cause scarring.

Although I'm leaning toward scarring, I couldn't definitively say what it is. It doesn't really look like scale, doesn't really look like mealies, but it doesn't really look like mechanical damage or sunburn, either.

Maybe someone else will be able to present some other ideas.

RE: Yellowing stems and white dots on leaves

I've had a similar situation due to spraying. Used a organic fungal/insect spray which gave many of the wide-leaved plants, white scarring.

Did you spray anything on or near the plant? I don't think its anything serious.


RE: Yellowing stems and white dots on leaves

Now that I think about it, I did spray something a few months back... Somehow skunks ended up in our backyard, they sprayed near the vents, and the smell was going through the rest of the house... I was told to spray a solution with rubbing alcohol on the surfaces of the room. I thought that I had taken everything out of the room when I sprayed... Hmm...

RE: Yellowing stems and white dots on leaves

The watery blisters around the brown scars almost indicate that the leaves are suffering from plant oedema.

It is not a threat to the plant's health, but becomes unsightly and is indicative of less than ideal growing conditions for the specific plant.

RE: Yellowing stems and white dots on leaves

Actually wetfeet is probably right. Mine don't have the raised blisters. I just have the white, dried scars from the spray.


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