Question

spotted leaves   QUESTION: my plectrelminthus caudatus, about 5" high in 3" pot started getting these dark spots then leaf yellows than falls off. they are in a 6x8 gh 2 small fans, thank you

ANSWER: Bill, it is not unusual for these plants to lose a lower leaf from time to time.  These plants should be treated like vandas. Growing them in a basket with a coarse potting mix for drainage may help.  I noticed that your potting mix looks damp and in a water retentive mix.  Hang the plant where it gets more air. This plant needs to dry off before rewatering. It wouldn't hurt to spray it early in the morning with kocide or another copper salt compound as a deterrant to fungal growth which can happen if the atmosphere is very humid or the potting mix is water retentive.

You might want to check with Oak Hill Gardens (www.oakhillgardens.com) where Greg Butler or Hermann Pigors has sold these plants and may have additional suggestions.   

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spots on leaf   QUESTION: thank you Wayne for answering so quikly. but just to make sure, im changing the mix and ill go and try to find some okcide, but this wasnt the bottom leaf, heres another picture, just incase you have a different idea

Answer
Thanks Bill.  That is a much better picture.  You will lose the bottom two leaves.  There are early sign of chlorosis on another leaf so it appears that the wet conditions which foster fungal growth are causing fungal spores to spread.  I would remove  the two lower leaves as they no longer serve a useful function and could facilitate the spread of fungal spores. You can expect to lose a third leaf eventually. After you obtain the fungicide, I recommend you drench the entire plant before repotting it as I suggested.  Keep it on the dry side and spray it weekly with the fungicide.   If you decide to visit the Oak Hill Garden site, get their E-mail address and e-mail them.  They specialize in orchids and grow species from seed.  Ask them to take a look and for any suggestions they might have.  You may mention my name in your inquiry as the grower Lisa and her father Hermann know me.  I bring this up as they have more experience than I with this particular species and lecture on plant diseases and treatment.  It never hurts to get a second opinion.