Wednesday, October 17, 2012
Citrus limetta, the Sweet Lemon Mosquitoes Hate
There's just such a lemon known as Citrus limetta, also known as sweet lemon, sweet lime, and Mediterranean sweet lemon in English, and as limu shirin in Iran, moosambi (Hindi) or sathkudi (Tamil) in India, and sometimes as mosambi or musambi in international trade.
While this "sweet lemon" is something of an acquired taste, it is sweet enough to be used to make lemonade without sugar in much of north Africa, South Asia, and the Middle East. In the native Citrus limetta, short-lived flowers of the sweet lemon are white, about an inch (20 to 30 mm) wide. The skin of the ripe fruit is slightly bumpy and light yellow, and the pulp is greenish-yellow. Sweet lemon juice is a mixture of sweet and sour, more sweet than sour.
The native sweet lemon is propagated by seed--although I haven't yet had a lot of success with this. It's a lot easier just to buy a Millsweet Acidless Limetta, a hybridized limetta tree.
The difference between the hybrid and the native plant is the color of the blossoms and the fruit--both purple. In other respects, the Millsweet variety is just like the native plant.
Citrus limetta is the tree you want if you want to make your own sugar-free lemonade from your own lemons. But the additional benefit of sweet lemon fruit is that the rind can be used to make a natural mosquito killer after the pulp has been used for juice.
Citrus limetta extracts are used as a mosquito larvacide. They poured into standing water, such as unused swimming pools, stagnant puddles too large to be drained, and other small bodies of stagnant water to kill mosquitoes still in the larval stage.
The extracts won't kill fish or amphibians, or pets or wildlife that stop to drink. The most potent mosquito larvacide would be made by soaking the peel in hexane, boiling off the hexane, and putting the extract in standing water.
I have an easier method. Just toss the used sweet lemon halves in the water you don't want to hatch mosquitoes. It's not 100% effective, but it's a great way to recycle your lemons after your make your sugar-free lemonade. There is just one caveat for using Citrus limetta to make sugar-free lemonade.
Studies in Sudan, where the fruit is very popular, have found that the juice interferes with the human body's ability to absorb chloroquine, a standard prophylactic treatment for malaria. Don't drink sweet lemon beverages when you are traveling to locations where malaria is endemic, unless you are taking a different kind of anti-malarial medication. Enjoy sweet lemon from your own garden--or your local greengrocers--at home.
Photo by James Steakley, taken at Missouri Botanical Garden. Via Wikimedia Commons.