The Thompson-Nicola Regional District (TNRD) Mosquito Surveillance and Reduction Program mosquito control contractor is noticing significant mosquito numbers in some communities around Kamloops. Areas like Barnhartvale, Dallas, Juniper Ridge, Deloro, Tobiano and others are being pestered by vicious little yellow mosquitoes. The contractor has been working through the week and will continue through the weekend to try and find the sources of this outbreak. They have visited dozens of known habitats and have flown over the problem areas in a helicopter to search for standing water. The contractor will continue to have staff visiting known habitats over the weekend. In the last two days, the contractor has located one source on Barnhartvale Rd and one near Tobiano Golf Course, but expects that there must be others.
The species causing the current problem (Aedes dorsalis and Aedes campestris) typically develop in alkali grassland ponds and over-irrigated hay fields. As little as 2 to 4 centimeters of water left standing for 4 to 10 days in the corner of a field, or in some cattle hoof prints, can allow these species to develop. These species do not come from flooding of the North or South Thompson Rivers (which produce different species), nor do they come from rain barrels, ornamental ponds, or swimming pools (these are different species as well). Once mosquitoes emerge from standing water, they seek long grass or other brush to hide from the sun. When it is hot, the mosquitoes will live a shorter life than when it is cool and wet. It is anticipated that the first hay will be harvested soon, and this typically results in some mosquito relief since the biters have less area to hide out in.
The TNRD Mosquito Surveillance and Reduction Program contractor treats mosquitoes while they are in their larval stage in the water with a biological control, Bacillus thuringiensis var israelensis. Once the adults emerge (the biting stage), the contractor is unable to help since the TNRD does not “spray” for adult mosquitoes. Residents that are being affected by this outbreak can use insect repellents containing DEET (like deep-woods OFF), or picaridin (Icaridin) on any exposed skin, and should wear light-coloured, loose-fitting clothing, especially at dawn and dusk. Products containing citronella, garlic, oregano, mint, tea-tree oil, etc, are not shown to be effective (nor is spraying Listerine or feasting on bananas, for those that have seen the Facebook posts). If anyone knows of a potential habitat or has any questions about mosquitoes, they are encouraged to call the mosquito advisory line at 250-372-5700.