Treating Mealy Bugs on Indoor Plants
If you notice a little ball of white fluff on one of your plants, take a closer look. You may have a mealy bug problem. There are many kinds of mealy bugs but the one that seems to be most common in houseplants in North America is the citrus mealy bug. In as far as your houseplants are concerned, the name has nothing to do with citrus fruit, nor with the fact that you may enjoy eating oranges and grapefruits.
Adult citrus mealy bugs are not very mobile and especially like to congregate tightly in protected parts of the plants such as in the crevice where leaves join the stem. You will also find them on leaves, especially young tender ones. The adults are covered in a hairy waxy coating that has a slight pinkish hue. Younger mealy bugs are very mobile, darker, not covered in hairy wax, and can easily move from one plant to another in search of tender leaves and stems where they latch on and start draining fluids from the plant.
Mealy bugs are difficult, but not impossible, to get rid of.
The first thing you should do is isolate and treat the infected plant. You should also isolate the neighboring plants as they may be infected too. Be sure to wipe down any surfaces like window ledges in between the plants to kill any stragglers with insecticidal soap.
To get rid of mealy bugs, be sure to wet all surfaces of the plant including any crevices or cracks in the stems where they may be hiding with insecticidal soap. Be sure to retreat again with insecticidal soap after 3 or 4 days. One of my biologist friends dabs the mealy bugs he find with a Q-Tip dipped in rubbing alcohol. This is VERY labor intensive and, he says, has never helped him to completely get rid of the problem completely. In a recent blog post, I recommended neem oil as an alternative to insecticidal soap. Several people wrote to me to suggest that a combination of insecticidal soap and neem oil works best. I.e. apply the insecticidal soap, repeat the application a few times and then take the neem oil approach. The advantage of neem oil is that it stays on the plants and makes them unpalatable to new croppings of mealy bugs or other pests as they hatch. Soap is generally not effective once it has dried up.
Mealybugs are indeed very difficult to get rid off. It seems that there is always one that the treatment misses, and all it takes is one to spawn a whole new population. I have heard that there are predator bugs (Cryptolaemus montrouzieri) that eat them. I haven’t tried them but I think I will give it a try one day. Check this site out for a description: http://greenmethods.com/biocontrols/cryptolaemus/
Has anyone tried these bugs?