Question
I have a about 35 orchid plants.  There is white fuzzy stuff on the underside of the leaf of most all of them.  On the top part of the leaf is yellow spots, in the same area of the white spots.. I remove it but it still comes back. What I need to know? Is what to spray them with to kill the stuff..

Thank You,

Sharleen Lopez
Wesley Chapel, FL

Answer
Hello Sharleen,

White fuzzy stuff on the underside of leaves usually means mealybugs and it sounds like you have a major invasion of them!  You can verify that they are mealybugs by dipping a Q-tip in isopropyl alcohol and wiping them off, the white fuzzy disappears exposing the small body of the mealybug.  

While you can try wiping them off, more appear to take their places because there probably are hundreds if not thousands lurking down within the potting media waiting their turn to come up to feed on the leafs.  

To get rid of them will require some work by you, namely repotting all 35 orchid plants.  During repotting, I'd recommend cleaning up the leaves by wiping all of the leafs one-by-one with a soft cloth dipped in alcohol.  After cleaning, you can repot it then go to the next orchid and do the same.  

Also, go to your local nursery and ask for a systemic insecticide that is recommended for orchids and use it according to the directions.  It will require three applications, one week apart to ensure you get any that may have been hiding as you cleaned them.  

It would also be a good idea to thoroughly clean the growing area before moving the orchids back, you don't want to chance that there might be some lurking there, waiting for the orchids to return.  

Hope this helped.

Jim Kawasaki
San Jose, Ca.