Silver mottling/spotting on leaves in terrarium
 

So I have a few issues going on actually, lol...

My original terrarium build apparently didn't have enough air flow so almost everything died from rot. Redesigning it with more air flow allowed those that survived to actually thrive! Example, one leaf left on my Dracula lotax and suddenly three more leaves appeared as the old leaf died off. Given the success, I bought a larger terrarium so I could possibly have a few more in there. Unfortunately, it means regulating everything all over again as well.

Recently, I started noticing a silver spotting and mottling on a few leaves. I sprayed using fertilome Triple Action Plus for insects, fungicide and mites as I assumed it was a mite issue. I left the door and top open so the chemical fumes could be released.

Since spraying over two weeks ago followed by two more spraying sessions weekly, the mottling has continued to spread. One Masdevallia dropped all but one of it's leaves. Two more Masdevallias are also dropping leaves, but both were recently repotted and only one has the silver leaf look. I am assuming the dropping leaves are from repotting and possibly the chemicals getting on the roots.

Would anyone be able advise with what they think is going on and possible treatments? Thanks!

Here is a picture I just took for reference.
http://img.tapatalk.com/d/14/07/20/yqugu5yt.jpg

:bump:

That looks to me as if it could be spider mites. Try wiping it with a wet paper towel on the under side of the leaves, if is is mites you will see red residue on the towel. Or use a magnifier to look at it...Jean

Jean, I did as you suggested but never knew the paper towel should be moist! Learn something new every day, lol...

I did the wet towel this morning under many of the leaves exhibiting signs. At first, I was getting nothing, then on one leaf I got three tiny reddish dots. Overall though, I really got nothing. So I'm assuming the past few weeks of spraying must be doing something right, but more spraying is needed for a few more weeks.

What is your take on the leaf drop issues? I'm assuming at this point it's a combo of repotting, spraying and mites for those two I repotted, and just the spraying and mites on the others.

I think you are probably correct, a combination of those 3 things could be a problem, but if you need to do it then what choice do you have?
By the way, how do you like the outside growing structure that you built a couple years ago? Haven't seen any pics of that for awhile...Jean