Answer: You could plant some things that are reportedly mosquito repellent around the area. Some choices are: Citronella plants, citronella grass, 'Citrosa' geraniums and thymus citriodora. They are available from Richter's Herbs at http://www.richters.com. I really don't know how effective these are against masses of mosquitos, however,
I think you are referring to "mosquito biscuits". They are little donut shape rings that you float in rain barrels, ponds, birdbaths, etc. that are imbedded with a bacterium (Bt 'Israelensis) that kills mosquito larvae. They last about 30 days. They don't stop the mosquitos from laying eggs, but they stop the eggs from hatching. You can usually pick them up at garden centers that sell pond supplies, or try Gardener's Supply Co. at ph. 800-863-1700.
Also, you might try a recirculating pump that moves the water around. Standing water provides perfect conditions for the mosquitos but if you create some 'wave action' it might help. (In nature, they look for these standing pockets of water, as opposed to flowing creeks or lakes with surface action.) Finally, some purple martin houses to attract these birds to eat the nasty biters that do hatch!
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