Question
QUESTION: I recently acquired a phal. Since I got it, two new flowers and a new bud.  Leaves look great except for a couple.  I just noticed they are turning purplish.  This is not on the older leaves, nor the youngest.  I don't know if it is due to a fungus, insect or virus.  Overall the plant looks great but am worried this is just the beginning of something awful.  Any idea what this could be?  


ANSWER: It doesn't sound like something caused by an insect or virus.  Generally, coloration toward the purplish part of the spectrum is the result of light levels and/or temperatures that were a bit too high for phalaenopsis. Generally, retailers aren't prepared to grow a plant over the long run so don't watch their growing conditions very closely.  Phals are houseplants and do best in an east window inside. When it is done flowering, you should buy a bag of orchid potting mix and repot it.  Be sure to wash the roots thoroughly and remove any mushy roots (healthy roots are firm) before repotting.

If your light levels and growing conditions are fine, the new leaves should be a yellow green in color.

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QUESTION: That is interesting as it appears the leaves that are "affected" are those tucked behind the others.  I do have this in an east window.  I have noticed flying insects and also some hard little "dots" on these two leaves as well.  My question, if at some point I do need an insecticide, do you recomment Shutlz for indoor plants which contains Pyrethrins, canola oil and inert ingredients.  You are most helpful and I have read many, many questions and answers - your time and attention is appreciated.

Answer
Cheryl, see if the "hard dots" come off with a q-tip and rubbing alcohol.  If so, these are scale insects and treatment is needed.  The initial treatment is to remove as many as you can see using the alcohol and cotton swab or q-tip.  Then, you will need to unpot the plant and rinse the plant (leaves and roots) with a hose or other water spray until both are clean.  Scale not only affects the leaves but other growing parts of the plant and the potting mix, so discard the old potting mix and clean the pot thoroughly if you intend to reuse it. Get a bag of orchid potting mix before unpotting the plant and repot in fresh potting mix.

I haven't used the Shultz for scale.  It might work.  I use a spray called "Eight" which is also a mild insecticide.  Spray all parts of the plant (including the roots) before repotting.  After repotting, monitor the plant periodically to detect any return of this insect.  The scale insect not only has the adult stage, which you may have noted, but it has a crawler stage which is less visible and more easily overlooked.