Q. My indoor orchids all of a sudden have developed some sticky sap on the underside of the leaves and flower stalks. Is this bad? And if yes, then what can I do to eliminate this problem. I wrote to Sunset magazine twice, but haven’t received an answer. August 2014
I love your articles in the Monterey Herald. They are always so informative.
A. It’s most likely that the sap is produced by very small pests that suck the plant’s juices. These might be aphids, mealy bugs (cottony blobs) or scale (bumps that slide off). Use a bright light to spot them, looking closely at the new leaves in particular. Eliminate the pests by wiping them with rubbing alcohol on a cotton ball or Q-tip.
If t you can’t see any pests, the sap might be produced naturally by some orchids to attract pollinators. If that’s the case, it’s not a problem, but some growers will wipe off the sap with a damp paper towel.