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February 07. 2016 12:01AM Since You Asked: Reader worried about mosquitoes, Zika virus The Zika virus is scary even though we are not supposed to have it here in Oregon. My backyard is poorly drained, and I have pools of water standing there, sometimes for many days. Is there any safe substance I can sprinkle on the water to make sure no mosquito larvae can breed there? — Bob Several Oregonians have been diagnosed with the Zika virus after traveling to tropical countries where the virus is spread by mosquitoes. At this point, experts don't think the virus will spread via mosquitoes in Oregon because we don't have its host mosquito species, Aedes aegypti, living here. But uncertainty remains, according to Jackson County Vector Control District Manager and biologist Jim Lunders. "All of the cases so far have been imported cases where people traveled, contracted the virus and came home," he said. "We don't have the species of mosquito of worst concern, but there's no 100 percent certainty a mosquito we have can't transmit it. We don't know yet." What is known is that our local mosquitoes can spread other diseases, so the district takes the annoying bloodsuckers seriously. Lunders said Jackson County residents can call the district, and staff members will analyze their property, check for larvae and recommend the best treatment plan for the situation. Mosquito larvae grow in water, so eliminating standing water in tree cavities, old tires, buckets, clogged rain gutters and other sources is the first line of defense. Bird baths and pet water dishes should be cleaned regularly since anything that holds water for seven days can produce mosquitoes, according to the district. At this time of year, there's lots of standing water, but mosquito larvae don't start growing until spring, Lunders said. If the standing water in your yard remains a problem as the weather warms, vector control staff can examine the water and come up with a solution. "We would rather make sure it's controlled correctly so it's not a problem for the whole neighborhood," Lunders said. A potential product that could be used in standing water is Bti, the naturally-occurring Bacillus thuringiensis israelensis bacteria. Bti products are also sold in hardware stores, but must be applied at the right time to kill mosquito larvae. Some formulations last for an extended period of time and are therefore easier to use effectively, Lunders said. The district also uses different insecticides that can kill mosquitoes in either their swimming larval or adult flying stages. In the spring, the district gives away mosquito larvae-gobbling mosquito fish to residents for use in specific situations. The fast-reproducing, non-native fish can be stocked in man-made ponds and water features outside flood plains that are not connected to natural waterways such as creeks and wetlands. Mosquito fish would not be a good choice for the standing water in your yard because they would die once the water dries up, Lunders said. The district has two breeding ponds for mosquito fish at its 555 Mosquito Lane location in Central Point. The fish will likely become available to the public in early May, according to the district. While the Zika virus is grabbing headlines lately, Lunders said more tropical diseases carried by mosquitoes will likely make their way to the United States. Oregon is already home to the West Nile virus. "That's why it's important to do mosquito control work, surveillance and testing," he said. For more information about mosquito control and for help combating the insects, call the district at 541-826-2199 or visit http://jcvcd.org/ . — Send questions to “Since You Asked,” Mail Tribune Newsroom, P.O. Box 1108, Medford, OR 97501; by fax to 541-776-4376; or by email to [email protected] . To see a collection of columns, go to mailtribune.com/youasked . We’re sorry, but the volume of questions received prevents us from answering all of them.   http://www.mailtribune.com/article/20160207/NEWS/160209807 © 2016 Copyright © 1995-2011 Crain Communications Inc. All Rights Reserved. Terms of Use Privacy Statement -->