It’s that time again – mosquito season! It seems people and mosquitoes alike are welcoming the warmth. Within the Lower Mainland, mosquito eggs laid in previous years along the banks and seepage sites of the Fraser River are hatching and beginning to emerge as adults. Floodwater mosquito eggs are triggered to hatch in the presence of water, typically from the freshet, and when the weather starts warming up and snow melt increases the levels of the Fraser River.

 

The greatest number of adult mosquitoes emerge – when mosquito pupae become adults – in association with the peak in the Fraser River.

 

Mosquito control contractors for the Fraser Valley Regional District are here to help. Morrow BioScience Ltd. (MBL) provides mosquito control services throughout the Regional District and have been conducting mosquito control within BC for over 4 decades – for over 20 years within the Lower Mainland. Residents may notice mosquito control contractors in brightly coloured vests sampling the flood and seepage waters for mosquito larvae – the life stage targeted duringmosquito control. Once the mosquito eggs have hatched and the larvae have started to develop, mosquito control contractors apply a bacterial larvicide to the seepage water to kill the larvae.

 

The larvicide is made up of bacterial spores toxic specifically to mosquitoes and black flies. When the mosquito eats the bacteria, it dies quickly. Mosquito development sites within the region will be monitored once or twice weekly through early August.

 

Mosquito control contractors have been applying the bacterial larvicide by ground since early

May. Helicopter treatments have also begun. Treatments may continue through the summer, as dictated by environmental conditions necessary for floodwater mosquito development. The

larvicide is not toxic to people, wildlife, or pets. We understand that this year, possibly more than most, residents will be spending more time at home, likely outside with friends and family. We are doing our very best to reduce floodwater mosquitoes so that they remain at tolerable levels.

 

Residents can help by reducing container mosquito breeding sites around their properties, by .

removing or refreshing standing water daily. These areas include bird baths, old tires, clogged

gutters, animal troughs, and kiddy pools, to name a few.

 

We also encourage residents to reduce their exposure to mosquito bites through personal

protective measures such as wearing long-sleeved shirts and pants, choosing light-coloured

clothing, using insect repellent, deploying mosquito netting at home, and ensuring window

screens are properly installed and maintained.

To report standing water or adult mosquito nuisance, please call the Fraser Valley Regional

District’s Mosquito Hotline:

1-888-733-2333

Or email:

mosquitoes@fvrd.ca

Please visit our website to learn more about mosquitoes, read FAQs, and access our blog:

www.morrowbioscience.com

 

Frequently Asked Questions (FAQs)
Question 1: What type of mosquitoes are controlled by Morrow BioScience Ltd (MBL)?
Most mosquito control programs operated by MBL, including the Fraser Valley Regional District
program, focus on mosquitoes that develop in floodwaters, primarily during the Spring freshet.
Certain programs within BC also have snowmelt mosquito species.

Question 2: What is the lifecycle of floodwater mosquito species within the program area?
Source: North Shore Mosquito Abatement District (https://www.nsmad.com)
Floodwater mosquito eggs are laid in the damp substrate along floodwater corridors. Flooding
along with other environmental triggers allow for the eggs to hatch into larvae. The larvae go
through four aquatic instar stages, which are also the primary feeding stages, prior to developing
into pupae. Pupae then emerge into adults. The development process can take as little as four
days in some species and conditions to as long as two weeks. Development times also depend on
ambient and aquatic temperature; warmer water resulting in accelerated mosquito development.

Question 3: What does MBL do to control mosquitoes?
MBL applies a larval control product to mosquito development areas. The active ingredient is a
soil-borne bacterium, Bacillus thuringiensis var. israelensis (Bti). When the mosquito larvae eat
the bacterium, they’re killed quickly.

Question 4: Is the larval control product toxic?
As a naturally occurring bacterium, the larval control product is considered non-toxic to, fish,
amphibians, reptiles, mammals, and most insects.

Question 5: What diseases can mosquitoes transmit in Canada?
In Canada, mosquitoes have been shown to transmit West Nile virus, Eastern Equine encephalitis
virus, and California serogroup viruses. West Nile virus is the most widely distributed vector borne
disease in North America. As the climate in Canada becomes warmer, the environment is more
hospitable to additional vectors and associated viruses.

Question 6: Can mosquitoes act as a vector for COVID-19?
At this time, there is no evidence that mosquitoes are involved in the spread of COVID-19 (SARSCoV-
2). It is thought that the COVID-19 virus may not survive the internal processes of the
mosquito. Other supportive evidence for the inability of mosquitoes to act as vectors COVID-19 is
that other Coronaviruses have not proven transmissible through mosquitoes.

Question 7: Is West Nile virus a concern in BC? What are the most recent levels?
West Nile virus (WNv) is only a slight concern in BC given the relatively few number of mosquito
pools, birds, horses, and humans who have tested positive. From 1 January – 12 October 2019,
one positive human WNv case was detected in BC. In that same year no animals, no mosquito
pools, and no birds tested positive for the virus. Certain container mosquitoes are WNv vectors.
In warmer seasons, more container mosquito breeding occurs, leading to greater potential for
WNv transmission.

Question 8: What can resident do to help reduce mosquitoes around their property or in their
communities?
• remove or refresh standing water daily in the warmer months,
• ensure that outdoor plants or containers have a drainage hole,
• clear rain gutters of debris and make sure they drain,
• turn over wading pools when not in use,
• install screens on windows and doors, and
• report standing water to your local mosquito control technicians.

Question 9: How can residents get more information or contact MBL?
Website: morrowbioscience.com
Fraser Valley Regional District Mosquito Hotline: 1-888-733-2333
Fraser Valley Regional District Mosquito Email: mosquitoes@fvrd.ca
MBL Mosquito Hotline: 1-877-986-3363
Email: info@morrowbioscience.com