Mosquitoes seek me out in a crowd, leaving behind swollen, ridiculously itchy welts. They seem to ignore everyone around me. Admittedly, this is an annoyance and not a serious medical condition. However, nearly a billion people are affected by mosquito-borne diseases worldwide, so controlling mosquitoes is a serious and much researched topic.
There are definitely ways to lessen the chance of being the mosquito’s victim and a few popular beliefs which are not widely supported by research.
The scented geranium (Pelargonium citrosum, “Van Leenii”) has become known as “The Mosquito Plant.” Unfortunately, repeated studies have proven that the plant has no mosquito repellent properties, either in plant form or when the leaves are crushed to release the volatile oils. While the leaves have a lemon scent, they do not deter mosquitoes. Grow this scented geranium to enjoy it, not for bug protection.
Likewise, fragrant plants such as rosemary, catnip, lemon thyme, eucalyptus and peppermint will not repel mosquitoes. According to Colorado State University, although widely touted for repellant abilities, there is no reliable data to support that these plants or the oils released when the leaves are dried will repel mosquitoes.
The volatile compound from the citronella grass (a hard to find tropical plant) does have satisfactory mosquito properties, discussed below. But it can’t be stressed enough: simply growing any plant in the landscape won’t deter mosquitoes.
So what is effective?
Eliminate standing water. Stagnant standing water is an invitation for the female mosquito to lay her eggs. She can breed in as little as one teaspoon of water. The egg-to-adult stage takes just four days. With one human bite, the mosquito extracts enough protein (our blood) to lay up to three hundred eggs. Yikes.
Check drip trays, gutters and downspouts frequently. Birdbaths and water features are big breeding grounds. Change the water often (twice a week is recommended) or use a bubbler to keep the water moving.
Mosquito dunks, a larvicide which is harmless to organisms other than mosquitoes, can be added to ponds to kill mosquito larvae. Rain barrels should be installed with a protective cover and spigot.
Encourage beneficial visitors. Spiders and other insects feed on mosquitoes so avoid or limit the use of insecticides. Bug zappers which indiscriminately target the “good guys” have been shown to have little effect on mosquitoes, too.
DEET repellent. Skin lotions and sprays containing DEET, a highly effective chemical compound, have been used since the1950’s and are often combined with citronella oil. While not without its detractors, DEET offers relief to many. Apply it on top of sun protectant and not under clothing. Always wash it off when you go inside.
Dress defensively. Mosquitoes won’t bite through clothing. Closed shoes, socks, long sleeves and long pants do help. Clothing treated with permethrin also offers some benefit.
Burn citronella candles.The smoke or vapor from citronella candles provide some protection in the immediate area, such as a patio.
Create air movement. Mosquitoes dislike moving air so a fan on a porch or patio will discourage visits.
I’ve not had the first bite of 2019 yet and by practicing some of these tips, I’m trying to reduce the bumps and lumps left behind by these buzzing nuisances. Here’s hoping…
Mosquito Management. Drs. Frank Peairs and Whitney Cranshaw, Colorado State University
Written by Linda McDonnell, Denver County Master Gardener
Image courtesy of Pixabay.com