Let's hope the rain comes this week as forecast as that will help reduce spider mites. These sucking insects create stippling on the tops of leaves. If you turn over a damaged leaf, you will find yellow or brown dots. The dots are where the mites have been at work, while the brown is fungus that forms in the punctures.
Insecticidal soap can help reduce the populations, or horticultural oil may be used. A hard spray of water with a hose can help as well. Orchids with thin leaves (such as grammatophyllums and scorpion orchids or Arachnis flos-aeris)
are frequent targets.