Lake Barcroft Mosquitos

The following information about mosquitos in our community was originally posted to the Lake Link on 16 March '03 by Diane Davidson, Environmental Quality Committee Chair. Information about Mosquitos and BT was posted to the Lake Link by David Howe on 14 March '03.

-Diane Davidson

Thanks to all those who provided information about the mosquitos. According to my research, it is very unlikely that we have a problem in the lake because the mosquito larvae do not survive in moving water. And there are predators in the lake. I would guess there is a chance that if we have a very dry, drought-like spell there could be some coves that get stagnant for a while because the water in the lake is moving more slowly and doesn't flush out that cove, but as a general rule that should not be the case.

About the concerns on Rusticway -- my husband and I used to live on Barger and had lots of vicious mosquitoes. And yes, they were the Asian tiger mosquitos. Unfortunately these little devils are around day and night, as opposed to the older breeds of mosquitos we are used to that were primarily nocturnal. Moreover, they breed very very quickly and also destroy other breeds of mosquitos in their territories, so that in a short time they pretty much take over. I hate them. In any event, they can breed in a matter of hours in as little as a tablespoon of standing water. Water collects in your gutters, flower pots, lids, garbage cans and lids, recycling bins, bird baths, patio furniture, low spots in your yard that don't dry out quickly, and lots of other places because it takes so little standing water for them to breed.

It is up to the homeowner to vigilantly get rid of all standing water, and that is very hard to do. Gutters are a big problem, especially if leaves or small branches, etc keep them from completely draining, thus allowing pockets of water to remain. To the extent that you can identify and diligently empty standing water, you can decrease the opportunities for these things to breed. You can also spread DT in gutters and low areas to kill larvae, but you must read the labels for warnings about exposure to children, pets, etc.

LBA has increased the number of bathouses around the common areas because bats are a natural predator of mosquitos. No matter how many bats we have, they'll never eradicate the mosquitos. I have also heard very positive reviews of the mosquito magnet. The drawback is that one yard with a magnet can't clear much. For best results, groups of neighbors (at least those next door to you) all need to get them so the collective magnets cover the necessary range around your house. (Note the daisy-chain effect here.) Unfortunately mosquito magnets are quite expensive, so widespread use of them hasn't happened. But if you are very concerned, it may be worth it to you to get some. The good news is that the Tiger mosquitos stay in a relatively small range of where they were born, so a couple of magnets spread out can be effective against them because each magnet is successful in the same type of range.

DEET is the only effective repellent. You get some benefit from the weaker varieties, but not as much as DEET. Another help, believe it or not, is Bounce laundry softener sheets. As crazy as that sounds, it seems that mosquitos are repelled by the scent (not Snuggle, but Bounce). A friend of mine told me that and I've tried it -- and it does help, weird as it sounds. I sometimes tuck them into my sandals/shoes to minimize ankle bites. It helps, but I have to tell you after a while the strong Bounce scent bothers me (I'm sensitive to any strong fragrances), so I have to get rid of them and take my chances! FYI, there is a roll-on Cortaid that is the size of a Chapstick tube you can carry around to apply to itching bites. This does give a fair amount of relief. So does regular benedryl -- use at night because it is sedating. Obviously these products won't stop West Nile, but so far West Nile has not been a huge threat to most people. Not a perfect answer, but every measure is a balancing act. The County is monitoring these bugs and we keep up to date on what they are advising. If West Nile begins to provide a more widespread threat that results in increasing the range of people contracting a disease, obviously the County, and lots of other counties across the country, will develop and recommend more aggressive ways to kill mosquitos, and of course we will keep you up to date on what we know to determine, as a community, what we should do. For now, the disadvantages of using strong chemicals and sprays (they will affect more people than West Nile will) outweigh the current need.

If you have standing water in your ditches and it seems to create a breeding ground because you have lots and lots of mosquitos, report this to the County and they will come out and treat the ditches because this is related to road management rather than private property. Leo Suslow liked the product the county used because apparently they had smaller sized pellets compared to the BT available at Home Depot.

There has been some discussion that possibly LBA or WID could try to purchase some of that product in bulk to get a better price, and then individual homeowners could purchase it from LBA or WID. You must understand, however, that WID is established under specific soil and water conservation laws. Their job is to manage the dam, keep the lake clean, and minimize soil erosion. Anything not sufficiently related to those purposes is outside the scope of their legal authority and operation. Any attempt to budget expenses to purchase mosquito control products for private residential use would be tricky because their budget has to be approved by the Northern Virginia Soil and Water Conservation District, who makes sure the WID is operating as required under the laws that created them. It may be possible to justify mosquito control, but if WID was to purchase a bunch of product to pass through cost savings to residents and there was insufficient interest by residents such that only a small portion was then purchased from WID, they are stuck with it, and would have wasted the entire community's tax money to buy it. The same goes for LBA -- we don't have something like that covered in our budget, and wouldn't risk spending money without prior sufficient interest to justify the expense. Whatever LBA might spend on such products is paid by every resident because it comes out of your dues. LBA always carefully analyzes and justifies its expenditures because every new one adds up and requires more dues to pay for it. Both WID and LBA have to be careful to be sure each expenditure is fiscally reasonable and responsible.

Bottom line -- either organization has to know there is sufficient interest. Either organization is happy to investigate to determine if we could, in fact, get some sort of bulk discount and how much we'd have to buy to get the discount. But remember, this is no miracle product. It's merely a smaller sized pellet of the same product Home Depot already sells. So, there has to be a serious justification (at least more than half of 1,000+ homeowners) for either LBA or WID to invest in this. Moreover, there is then the administrative expense of distributing it -- neither organization is staffed for that kind of job. If you really want either of us to do that, realize that means more salary expense, and also storage requirements -- and none of that is free. Everyone in the neighborhood pays for it. Our initial discussions determined that this was not a proper area to get into because we couldn't justify the time, logistics and expense, particularly in light of the fact that the same product, in an arguably less convenient size, is available to anyone who wants to buy it at Home Depot.

As for the common areas, WID and LBA both keep watch, but again if you see pro blems with standing water at the beaches or other common areas, let us know. Beach storage boat owners -- store your boats upside down so water does not collect in the hull and remain there. Storing your boat properly is your responsibility.

Both WID and LBA are monitoring the Women's garden and are collaborating to devise an effective way to eliminate the wetlands area behind it that has unfortunately resulted from construction of the waterfall, etc. The area was regularly checked for larvae last year by LBA, and we found none. Any correction to eliminate the wetlands must be carefully crafted so that it does not inadvertently cause another problem. If we find larvae there, we will treat it.

The Fairfax County websites give a few other suggestions about what you can do to get rid of as many mosquitos as possible. The absolutely most effective way of reducing the mosquito population here is for each homeowner to eliminate standing water everywhere on their property. Locating every tablespoon of available rainwater (or from watering the grass and gardens) every day is obviously impossible. But each resident checking gutters, boats, furniture, flower pots, trash cans, recycling bins, any lids, window boxes, hanging flower holders, etc etc is the first answer to reducing the mosquito population. Private use of mosquito magnets can also help, subject to the limitations discussed above. -- Diane Davidson

Mosquitoes and BT israelensis
-Kevin Howe

BT is a naturally occurring bacteria (israelensis is a strain of BT) and this strain is well documented to be relatively non-toxic to most organisms except black flies and mosquitoes. And is is used is standing water. And, it is FAR better than other synthetic pesticides (e.g. organophosphates)IF you were going to use a pesticide.

But it has a very short effective life. It is a living organism so it dies and degrades rapidly; according to the scientific literature, it has a half-life of 3.4 hours under normal sunlit conditions (UV light really zaps it). BT is also said to be effective a maximum of 48 hours in water.

Mosquito eggs take 24-48 hours to hatch, the larvae live for 4-14 days and depending on the species of mosquito, the adults can live four to 8 weeks and then the cycle begins again.

Look at the size of Lake Barcroft (cost of treating) and the weeks involved in the life cycle of the mosquito and effective life of BT israelensis and it does not seem like a good idea to treat the Lake.

But even if BT worked well, I would not be in favor of treating the Lake with it. The mosquitoes aren't bad and every morning and evening in the summer I hear the fish lips gulping those crispy mosquito larvae; not to mention the bird beaks snapping the adults.

I would hate to see us upset the balance of this wonderful lake. West Nile Virus - a worry? Sure, but so are drunk drivers on Columbia Pike - should we spray for those too?? -- Kevin Howe