Yellow dust on leaves of Maxillaria
 

Hi,

Today I see this yellow dust-like specs underneath (on the bottom side) of my maxillaria desvauxiana. It is a new leaf, is this something to be alarmed about? it is so much, it does not seem like some insect, but I might be wrong?

That is probably spider mite damage. I would spray the entire plant with 70% alcohol or insecticidal soap. Be watchful; spider mites are always present. It is likely they are also on your other plants. They can be controlled by spraying the entire plant with water every 1-2 weeks.

Thanks for the quick response and the warning! it does not look like the pictures I can find on spider mites -- it is really much smaller and even, more like dust or pollen, and I don't see anything like a web. I could easily brush it off with a little bit of kitchen paper.

hm.. I'll isolate the plant for now, see if anything happens

Not all mites produce webs. As a side note, spider mites are not visible with a naked eye. You'll need a magnifying glass to see them.