If you’ve spent much time outside since the sun has returned to the Flathead Valley summer, then you’ve probably noticed that buzzing, biting pests have returned along with it. Heavy rain in June has led to conditions ripe for a high number of mosquitoes in Western Montana, according to the Flathead City-County Health Department.
Mosquito Control Coordinator Bruce Gunderson said he took the offensive during an early spell of warm weather in April, but heavy rain in early summer complicated his effort.
“A lot of that rain that came down pooled in several areas and created a lot of (mosquito) habitat,” Gunderson said. “Water stayed on the surface of the ground and has wreaked havoc.”
Mosquito Control staff has been challenged this season with rising water in low lying areas, creating prime hatching grounds for mosquito larvae. The high water activates mosquito larvae that may have been lying dormant for several years. Mosquito control staff have also had to wait for river levels to subside to access and treat backwater locations.
“Trying to find all the habitats on the valley floor is really difficult when you only have two people,” Gunderson said. “We are seeing pockets of infestation.”
Flathead County treats water containing mosquito larvae with larvicides approved by the Environmental Protection Agency like Altosid, which prevents larvae from developing into mosquitoes by mimicking the insect’s growth hormone, and Bacillus, a spore attached to corncob chips toxic to mosquitoes and black flies when eaten. Flathead County is one of only two districts in Montana that doesn’t use adulticides, according to Gunderson, which makes treatment tougher but less toxic.
The hatch is mostly over by now, and Gunderson spends much of his time collecting samples from traps to test for the presence of West Nile virus, and if it is detected the county will notify the public. However, only 2 percent of mosquitoes in the Flathead are the type that carry West Nile, he added.
To help mitigate the high number of mosquitoes, the health department recommends: draining and changing standing water on things like bird baths, wading pools and storage tarps; wearing long sleeve shirts and pants; staying indoors near dusk and dawn, when mosquitoes are most active; using insect repellant containing DEET; and to report areas of stagnant water to Gunderson at [email protected] or by calling 406-751-8145.
The county also recommends repairing screens to keep mosquitoes out of your home, cutting grass and weeds around your home short and removing grass clippings or garbage that can obstruct water flow in ditches or streams adjoining your property.
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