Ditch Your Window Screens and Banish Flies Naturally!

Spring is in the air, the plants are flowering, and life is returning...including the pesky insect kind. It's a struggle as old as time for humans to repel insects, and the home is one area of special concern. No one wants to find bugs chilling in their kitchen or climbing in bed with them at night. In addition to squeezing through cracks and under gaps in doors, windows are a traditional entry point for insects into the house. Until about 150 years ago, there was not a good way to enjoy fresh air and keep the flying bugs from coming inside. 

A failure in fly-paper, detail, from Puck, v. 16, no. 397 (October 15, 1884)

 

Window screens came into use after the Civil War, when wire mesh became easier and cheaper to manufacture. Despite the benefits, window screens were not universally hailed as savior of the summertime when houses would need to have the windows opened for ventilation. If you were not an early adopter of screens, what other method could you use to keep flies away from your open windows? The Daily Item in July of 1896 suggests an aesthetically-pleasing type of deterrent for houseflies - flowers.

Nearly every household at this period of the year suffers more or less from the plague of flies. Householders may therefore like to know that mignonette planted in boxes on a window-sill will keep flies from a room as effectually as wire screens. Geraniums have the same effect.

Mignonette was a flower I had not encountered before, but this herb (official name Reseda odorata) has long been kept in gardens or container planters. The flower is described at Floret as having "[l]ong, wispy stems. . . capped with creamy white flowers that have delicate orange centers and smell like vanilla." A perusal of other sources does not reveal any substantiated claims that the flowers or leaves of the plants are insect repellents (they are actually good pollinator plants, so you'd likely attract bees and wasps to your window!), but if you're interested in other uses for the flower and more pictures, check out this page. Geraniums, by the way, are citronella-containing plants, so they may help repel pest insects, particularly if you get a strongly-lemon-scented variety.

A much later article on exterminating flies for sanitary reasons expands the list of "offensive" flowers to include:

Any odor pleasing to man is offensive to the fly and vice versa, and will drive them away. . . . Geranium, mignonette, heliotrope and white clover are offensive to flies. They especially dislike the odor of honeysuckle and hop blossoms. 

None of the modern sources for natural fly and insect repellents claims these plants as effective, but the advice earlier in this article to spray lavender oil is (you can also use cinnamon if you prefer a spicier scent). If you want to pursue an insect-repellent window container, you'd do better with herbs like rosemary, lavender, basil, lemon balm, maybe mixed with a few marigolds.[1]

Of course, insects can get inside whether or not you have window screens. Was there any way to make your house less appealing to them once they arrived in the great indoors? An unspecified researcher somehow conducted preference tests with houseflies on their favorite colors. The results were shared in the Big Stone Gap Post on August 28, 1912:

Someone has found out that houseflies have a preference for certain colors over others. Tests were made and it was discovered that they like green best, then red, and that they dislike yellow, brown and blue. The investigator thinks that by choosing wall paper for the house that is blue for instance you can make your home unwelcome for the pests.

If you're entertaining thoughts of repainting your home's walls into fly-free shades of blue, think again - modern research has now stated blue is a fly's favorite color! The article claims "that flies are three times more attracted to the color blue than to yellow and that yellow actually seemed to repel flies." A similar study using strips of fabric corroborated a preference for dark blue and sky blue, with yellow on the disliked list.[2] 

Blue as an insect-repellent color is a common folk belief, and while the color itself might not have done the trick, there's a theory the chemicals found in milk paint might have been the key deterrent. The same may go for the newspaper recommendations for heliotrope and some honeysuckle flowers. The yellow of these flowers may provide some visual deterrents, but don't rely on plants or paint alone to keep out the flies! Window screens are much more effective.

If all else fails, you can start cultivating Dionaea muscipula...

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