Question
My beautiful Hindu Rope plant has developed a white powdery substance on its leaves.  I have looked at it with a magnifying glass and it looks sort of like cotton, but when rubbed between my fingers it just crumbles - doesn't fly like a bug - I have used a spray on other plants that seem to have had this same problem and unfortunately it didn't work.  I would hate to lose this plant - it's just beautiful.  Can you help?  Thank you.

Answer
Hi Patti,

Based on your description, your Hindu Rope plant (Hoya carnosa) has a mealybug infestation. These critters don't look like bugs as they create a small mass of cotton-like stuff to protect themselves. Usually you will see a soft, amorphous body under the outer covering, but only if you look carefully. If they are completely dried up and powdery, they may already be dead. If so, then you can remove them with a strong spray or shower or with soapy water.

The difficulty with treating mealybugs is that there are always more to deal with than meets the eye. Young mealybugs lack the telltale cotton-like protective coating and they are skillful at hiding in nooks and crannies where leaves and stems join.

The key to successfully eradicating these creatures is to also spray the ones that are out of sight. That means that whatever treatment you select, you must get complete coverage, to the drip point, of all leaf and stem surfaces. If you miss a few, they will live to breed another day.

I do not recommend any pesticides because they are all hazardous to use and not 100% effective against mealybugs. You may want to try spraying with rubbing alcohol. Mix 1 part alcohol with 5 parts of water and add a squirt of liquid soap. Be sure to spray all leaf and stem surfaces thoroughly. The common practice of applying alcohol with a Q-tip is not effective because it misses the ones you can抰 see. It is also best if you repeat this treatment again in 5 to 7 days to catch any crawlers that you missed the first time. After that, you should check your plant weekly to see if they return.

Never spray in direct sunlight or when temperatures are above 75 degrees. It is also advisable to test any spray on a few leaves as a test before you spray the entire plant. Wait a few days following the test to see if there is any negative reaction to the spray

Please let me know if any of this is unclear or if you have any additional questions. If you would like to e-mail me some photos, I may be able to provide some additional insights.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

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