Gardening Topic for March 2010
What's Bugging My Houseplants?

Provided by the Western Massachusetts Master Gardener Association

By Marilyn Pease,
Master Gardener


As we are all good Master Gardeners, when we  moved all our houseplants in from their summer vacation spots in the yard, patio, or deckwe thoroughly checked for hitchhikers and freeloaders before bringing our plants inside. Yeah, right. I’m scurrying around at the last minute, flinging plants into the house willy-nilly trying to stay ahead of our first killing frost!

Ideally, we should be checking underneath leaves and on the underside of pots and carefully spraying off our plants in the shower or under an outdoor hose as well as treating any pests seen with the least harmful of insecticides. So much for an ideal gardening world. Several weeks after bringing in my night-blooming cereus, I noticed cottony white stuff at the leaf-stem joints on most of the plant. Upon examination with a hand lens, I spied lots of little tank-like critters under the cotton, probably some kind of mealy bug. (There are many types.) I carefully wiped the leaves and stems with a little rubbing alcohol and have not seen any since. Alcohol is a good cure for this type of indoor insect pest provided you do not overdo the application which can burn the leaves. Test a small patch first to see how the plant reacts.

Other common houseplant pests include fungus gnats, both the adult and larval form, the greenhouse white fly, aphids, scale and two-spotted spider mites. A good spray weekly with water will dispatch most of these pests. Neem oil or an insecticidal soap are also good, fairly safe alternatives for indoor use. Be sure to read the labels carefully and abide by all instructions.

Just by way of anecdotal information, my great-aunt used to save up cigarette butts in a can of water which she then used to drench the soil in her houseplant pots and also spray on the leaves. I do not have any personal experience using this method, so I cannot comment on its efficacy. There is plenty of information regarding homemade nicotine or other organic based home insecticides on the Internet which you should use with caution,
especially around pets or children. Nicotine, a neurotoxin, has been banned in commercial pesticides since 2001 due to possible food contamination and pollution runoff. An excellent website for information on dealing with houseplant pests in an organic fashion is . Click on the “Pest” tab.



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Provided by the Western Massachusetts Master Gardener Association