The RDOS operates a mosquito control service (see the RDOS site for information),  This thread is primarily about mosquitoes attributable to Max Lake, a conservation area to the north west of the West Bench (bordering Husula Highlands and Westwood Properties).

A thread on attempts to reduced mosquitoes at Max Lake using non-pesticide measures follows in this thread.


Update and summary as of 2 Jul 09: The RDOS is prevented from doing anything in and around Max Lake by a conservation covenant jointly held by the RDOS and The Land Conservancy (TLC).  We asked TLC on Monday, 29 June, 2009, to relax the terms of the covenant so that Max Lake can be treated under the terms of the RDOS Pest Management Plan.  The RDOS uses a very specific, naturally-occurring larvicide that is non-toxic to fish, amphibians, etc.  The TLC has refused this request.  Thus, there is nothing the RDOS can do about mosquitoes originating in the Max Lake area.  The only remaining option for residents affected by the mosquitoes is to take their complaints directly to TLC (contact info).

See also a new thread on West Nile.

I am getting a large number complaints from people in and near Husula Highlands about mosquitoes.  The following is fairly typical:

We are currently undergoing, what I can only describe as a siege of mosquitoes. We are no longer able to enjoy our garden, in fact, I do not allow our children outside to play—despite being covered in insect repellent (which I don't agree with having to do), they are still being bitten. We're being bitten through our clothes!  The presence of mosquitoes is significantly reducing the quality of our life—we no longer have friends over (it's quite frankly embarrassing to have them swarmed on as they walk from their vehicles to our home. We no longer garden—to be very honest, it's a very sorry state of affairs to have a beautiful garden and not being able to enjoy it—I feel as if I'm in a bunker, trapped inside

I certainly sympathize with Husula residents and have asked RDOS staff to clarify the issue (unfortunately, a key staff member has been on vacation, slowing down the process a bit).  As I understand it, the root of the problem is a "conservation covenant" placed on Max Lake in 2001 by its former owner (the Abundant Life Church) with the help of the RDOS and The Land Conservancy (please see TLC's overview of the Max Lake project).  The idea of the covenant is to restrict certain activities—such as pesticide use—in perpetuity in order to maintain the wetland.  The mosquitoes are ostensibly food for frogs, birds, etc. and thus eradicating the mosquitoes impacts the overall viability of the ecosystem.  In short, the covenant makes it illegal for the RDOS crews to eradicate mosquitoes in the protected area.

All I can say at this point is that I have asked high-level RDOS staff to look into our legal options with respect to the conservation covenant.  According to Steve Anderson, who takes care of mosquito control for the RDOS (see Steve's email messages below), the RDOS is permitted to spray for the type of mosquito known to carry West Nile (see the RDOS mosquito control page).  That is, public health concerns trump the conservation covenant.  I am not sure whether quality-of-life issues do the same.  Please stand by...


Email from Steve Anderson, June 5, 2009:

Max Lake was part of the Mosquito Control Program from when I started in 1989 thru the time it became a protected area. It is one of those sites that seems to hatch a large volume of Aedes, (floodwater), mosquitoes in the spring, and we confirmed that again this year. However, as the year progresses, and the water recedes, those floodwater mosquitoes are no longer as present in the water, and there is a more balanced mix of other kinds of mosquitoes and aquatic and flying predators that can help control the mosquitoes. Unfortunately, those floodwater mosquitoes are pretty aggressive biters and can be extremely bothersome and I believe those are the mosquitoes that are causing the problems for the nearby residents. They do not persist long however, and only produce one batch of eggs so after two to three weeks they become much less of a factor. However, we have seen Culex and other mosquitoes in the Max Lake protected area as the year progresses, and as these are possible vectors for West Nile and some other diseases—so it would be good to monitor their presence, and treat them under Interior Health's West Nile Pest Management Plan... but if and when we do that would have to be discussed with the people managing the property. In the meantime, I have clarified the borders of the protected area, and will have the mosquito control staff monitor and treat the areas nearby on a weekly basis for all of this summer, which is what we did last year. I believe their presence in the nearby areas will give us a good idea of how Max Lake itself is doing in terms of water levels, numbers of mosquito adults, the presence of natural mosquito predators and the levels of Culex mosquitoes.

Follow-on message from Steve, 10 June, 2009:

We were up in Husula Highlands yesterday after a quick check of the main part of Max Lake. The adult mosquitoes were very abundant of course, but from what we could see they were most likely the Aedes (floodwater) mosquitoes that we had observed in Max Lake this year. We were of course very uncomfortable that we could not have treated these mosquitoes—especially considering the specificity and safety of the larvicide we use. As far as mosquito control efforts, we are very limited to not spraying without the permission of the people managing the properties we would want to spray under our nuisance mosquito program's Pest Management Plan. However, I understand that in the past, we have been given permission to treat the Max Lake area for mosquitoes that can carry West Nile Virus, but have not been given permission to treat the floodwater mosquitoes which are the ones plaguing the residents. I would like very much to get permission to treat these floodwater mosquitoes in Max Lake in the future as we did before, especially as they can theoretically occur after every significant rainfall, so any discussions that could be carried out with the managers of the property.



From Mr Andersen's June 10th update, it surely sounds like we'll be getting another "plague" of those "floodwater" mosquitos which he suggests could theoretically occur after every significant rainfall (like the one this past weekend)!!! We had already lost one-third of our outdoor summer season due to the first wave of "floodwater" mosquitoes which appeared in early June ... so that leaves us with only August???

If any other organisms are supposed to be depending on these "floodwater" mosquitoes for their survival, they are certainly NOT around here (though the mosquitoes are happily surviving on us and our dogs).

Let's get some serious discussion going with the managers of the property to do some effective spraying.


Susie Latham

2127 Ryan Road

I dug up a copy of the conservation covenant on Max Lake.  It was established in 2001 (two Area F directors ago). I did not live in Area F at the time so I do not know how much public consultation was done, etc.  Perhaps someone else recalls the details.

The covenant is a legal device to limit the rights of the owner (any owner) of the property. It includes a long list of restrictions intended to minimize environmental impacts on the wetland and Section 5.2 (l) specifically prohibits the application of "any chemical, herbicide, or pesticide on the Covenant Area".  As I read it, there are only two situations in which these restrictions can be overidden:

  1. The owner can violate the restriction in order to "prevent, abate or mitigate any damage or loss to any real or personal property; or prevent potential injury or death to any individual."
  2. The owner receives written consent of the covenant holders, in this case the covenant is held jointly by the RDOS and The Land Conservancy of British Columbia.

Option 1 is a bit of a stretch given the absence of West Nile in this area (see here—careful what you wish for ;-).  We are trying Option 2.  Specifically, I have asked RDOS staff to send a written request to TLC asking for permission to treat the area as required for mosquito control.  If the TLC agrees, then I will make the same request of the RDOS board.

So here is the bottom line:  The conservation covenant exists and cannot simply be ignored.  The only way the RDOS can legally apply larvicide in and around Max Lake is with the written permission of The Land Conservancy (contact details).  The current owner (Inland Contracting) has no say whatsoever in the matter (indeed, that is the point of the covenant).  Sorry I cannot be of more immediate help.  If it is any consolation, we were up on Forsyth Drive on Saturday night and my whole family got eaten alive (even with repellant, citronella tiki torches, etc.)


Hi Micheal,

i am pleased to see that you  are at least looking into the problem,and I am also sure you probably received the notice in the mail about,Mosquitoes and West Nile, how appropriate was this for timing. I can only hope that something can be done soon as they seem to be worse right now, I average about 6 bites a day. And I am only in the garden for 20 minutes.seriously,this is a real problem right now.Something, has to be done,for health reasons maybe. If we all got together with the owners and explained that we don't really like being food for thte mosquitoes,that feed birds and frogs etc.

Hope to hear from you with some good news about this problem.

Trudy Dagg

I had a short discussion with a long-time resident of Forsyth Drive who explained that there was strong support from Husula residents for the conservation covenant circa 2000 due to the apparent threat of development occuring around Max Lake.  The covenant prohibits the application of pesticides but also prohibits development of any kind.  So that helps explains to newcomers how we got here.

A quick Google search led me to this article on mosquitoes from entomologists at the University of Kentucky.  Although Kentucky is very different from our region the same species of mosquitoes are found in both places. Some good background information here.

The fact that a covenant was created shows that there was (and likely still is) strong support for protecting Max Lake.  I just received the following email:

Although I agree that the mosquitoes this year have been worse than any other, we seem to have found a solution. I bought a black light mosquito zapper for $84 at Canadian Tire. It covers a 1 acre area. We sat out tonight at twilight for about 40 minutes and only had one mosquito  land on us. Personally, I would rather not use the pesticide solution at Max Lake. A teacher I know was just educating me this week about the pond study he usually does with his students regarding the importance of the Max Lake Wetland. Apparently, Painted turtles and Tiger Salamanders both reside there and both are on endangered lists. South Okanagan wetlands are unique ecosystems in Canada. I would rather put up with a few weeks of bothersome pests than do irreversible harm to the Wetland near our homes. When you choose to live in this neighborhood which interfaces with wilderness and a riparian wetland, you have to take the good with the bad. Think of the black fly season of June in Ontario, that is just the reality of early summer. I would advise others to buy the mosquito zapper and not lobby for the use of pesticides.


This data sheet from the manufacturer answers some questions you may have about VectoBac, the larvicide used by the RDOS.

VectoBac® is based on the naturally occurring active ingredient Bacillus thuringiensis israelensis (Bti) – highly effective, yet perfect for environmentally sensitive application sites. It provides economical control of mosquito, black fly, midge and filter fly larvae. VectoBac is offered in a variety of formulations to fit application conditions and breeding habitats.

I would like this person to come up to our place and see how the zapper works. The mosquitoes just laugh at it. We purchased our property knowing full well that Max Lake was monitored and treated with a non intrusive procedure. We enjoyed next to no mosquitoes for 15 years. As far as I'm concerned the Concervancy has devalued our property as I am sure it would be hard to sell if people knew the problem we have up here. Also we were bothered by mosquitoes all summer last year. I feel that our 

RDOS staff met with a representative of TLC on 29 June, 2009, to request permission to treat Max Lake for mosquitoes. What follows is a summary of the report I received from staff:

Bottom line: Based on the covenant TLC will not allow the application of any pesticides or chemicals including mosquito spraying.

RDOS staff pointed out the following:

  1. The larvicide used is considered specific to mosquitoes and non toxic to other organisms.
  2. Based on the "prevent potential injury or death" language in the covenant, it may allow spraying at some time in the future if/when sufficient numbers of these mosquitoes are present and a potential health risk is identified.

TLC is interested in working with us to monitor the area and collect data on the mosquito population at Max Lake.

  1. RDOS staff will work with the TLC to monitor the site and collect data on mosquito larvae present
  2. If we have statistics or science to support a quality of life argument, we can have another discussion with them.

Are you saying they won't even allow you to monitor or treat the for mosquitoes that might carry the bird flu virus????

RDOS staff will continue to monitor Max Lake for West Nile virus, which seems to be the largest health risk we face from mosquitoes.  As noted above, however, West Nile has yet to appear in this province (see the surveillance data from the BC Centre for Disease Control), so the immediate risk is very low.

Staff will also try to determine if Max Lake is the whole problem. I suspect it is, since the mosquitoes are clearly much less numerous once you get a kilometer or so away from the wetland. Even so, we ask you to walk around your property and take a look for standing water.

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