Wet weather just right for mosquitoes

TNRD mosquito programs for area

The Thompson-Nicola Regional District has a multitude of programs in place for battling mosquito control and the West Nile virus.

With mosquito season in full swing, here’s some facts, tidbits and useful information about everything mosquito related, courtesy of the regional district:

Nuisance mosquito control program

The TNRD has had a nuisance mosquito control program in place for more than 30 years.

The program is operated in electoral areas A, O, P, J and L and in Kamloops, Clearwater, Barriere, Sun Peaks, Chase and Logan Lake.

The program is operated by BWP Consulting Inc.

The majority of the program is focused on floodwaters of the North and South Thompson rivers and early spring snowmelt pools in the grasslands around Pritchard, Pinantan, Logan Lake, Knutsford, Paul Lake and Lac Le Jeune.

Control of nuisance mosquitoes is accomplished by monitoring more than 450 known larval development habitats.

When larvae are present, they are treated with a larvicide containing a metabolite of the bacterium Bacillus thuringiensis var israelensis (Bti). BWP Consulting Inc. uses between 10,000 and 12,000 kilograms of larvicide yearly.

Certified technicians in the field wearing backpack blowers do treatments.

Staff members put on waders and walk into standing water and use the blowers to apply the larvicide, which is attached to a corncob carrier.

When the major rivers flood and there is extensive habitat, a helicopter contractor is hired to apply larvicide from the air.

BWP Consulting Inc. monitors the standing water and instructs the helicopter pilot as to what water requires treatment.

They then follow the helicopter and act as ground support to fill the helicopter seeder.

The larvicide is safe for fish, birds, mammals, amphibians and reptile — and is even safe for other invertebrates and insects, other than mosquito larvae.

Nuisance mosquitoes are usually from the genera Aedes.

These mosquitoes generally emerge all at once and are aggressive and persistent mammal biters.

Most of these only bite once and then lay their eggs and die, so they do not have the opportunity of picking up West Nile virus and then passing it along the next time they bite.

West Nile virus risk reduction

The TNRD recently received $336,135 from the provincial government for its 2011 West Nile virus risk reduction initiative.

The TNRD has received funding from the province over the years for mosquito control, mosquito surveillance and public education for local residents and First Nation communities.

The TNRD has an additional 300-plus larval development habitats mapped for the West Nile virus program and monitors these, as well as the 450 nuisance sites for the presence of Culex mosquitoes.

Culex mosquitoes are the vectors of West Nile virus.

They have a strong preference for biting birds and lay multiple batches of eggs each summer.

Female mosquitoes bite to obtain protein to develop their eggs.

Culex mosquitoes bite numerous times in the summer, as they require one blood meal for each batch of eggs.

This means they have the opportunity of picking up the virus from an infected bird and passing it on to another animal when they bite again.

The population of Culex mosquitoes peaks in late July or August, when most nuisance mosquitoes have already died off.

Because people are no longer avoiding the persistence of the nuisance mosquitoes, they often let their guard down in these months and stop wearing mosquito repellent.

However, even though there are fewer mosquitoes in late summer, the ones still around are primarily the West Nile virus species, so people should continue to take precautions until mid-September.

BWP Consulting Inc. is now treating surface waters with Bti, using both blowers and helicopters in places such as the Nicola Valley.

They will also be treating nearly 4,000 catch basins with the bacteria Bacillus sphaericus in Kamloops, Chase, Barriere, Clearwater, Clinton, Cache Creek, Ashcroft and Lytton.

BWP Consulting Inc. is setting nearly 50 mosquito traps throughout the regional district and will be identifying mosquitoes captured to determine areas where West Nile virus species are present.

They will collect mosquitoes at these sites weekly for 10 weeks.

For more information about everything mosquitoes, contact Cheryl Phippen at bwp@shaw.ca or call the 24 Hour Mosquito Advisory line at 250-372-5700.

Additional information can be found online at tnrd.bc.ca.

The West Nile Virus Information and Bird Reporting Line is 1-866-300-0520.