Does BLSG threaten endangered species?

Nine species of bat live in Vermont, and five of them are so uncommon that Vermont has listed them as threatened or endangered species. The Vermont populations of these bats have decreased because of white-nose syndrome, a disease that started killing bats around 2006. All of the listed bat species spend the winter clustered in caves or mines where white-nose syndrome can infect new bats.

Scott Darling of Vermont Fish & Wildlife examines an Indiana bat captured during a workshop at the Salisbury Community School. August 8, 2008

Two of the state-listed bat species are also listed as federally threatened or endangered species. The northern long-eared bat was first listed as federally threatened in 2015 because its populations had declined due to white-nose syndrome. The Indiana bat was listed as a federally endangered species in 1967 long before white-nose syndrome was identified.

All five of these state and federally listed bat species live in the BLSG Insect Control District. The federally endangered Indiana bat has a large maternity colony at the northwestern corner of Salisbury and in neighboring Middlebury and Cornwall. In the summer, females raise their young and spend the daylight hours on large trees there. At night, Indiana bats fly throughout Salisbury and probably other District towns to feed on insects. Indiana bats are currently being studied in the BLSG District by Vermont Fish & Wildlife Department biologists.

We captured two Indiana bats that evening at the Salisbury Community School. A new pair of sterile gloves is used for each bat to prevent spreading diseases among bats. August 8, 2008

While navigating the landscape at night, Indiana bats often fly along the edges of forests instead of flying through forests or across fields (more here). This behavior can result in Indiana bats flying along roads that follow the edge of forests. Road corridors through forests are also followed by bats.

Malathion is a broad spectrum insecticide which is highly toxic to most types of insects and many vertebrate animals. The US Environmental Protection Agency (EPA) found that malathion is “likely to adversely affect” the Indiana bat and most of the other federally threatened, endangered, and candidate animal species. The EPA is currently being sued for failure to regulate malathion to prevent harm to threatened and endangered species.

In addition to a mist net, this harp trap was in place to catch bats. The vertical monofilament lines stop the flying bats which slide unharmed into the trough below. August 8, 2008

One of the primary control practices of the BLSG Insect Control District is to spray a cloud of malathion along roads after dark. It is therefore likely that the federally endangered Indiana bat will be exposed to malathion due to BLSG’s practices. This is exactly the type of situation which the BLSG was required to report in its application to be authorized to spray malathion. BLSG left that part of its application blank at great cost to local taxpayers.

The third bat caught was this northern long-eared bat, now a federally threatened species. Later, little brown and big brown bats were also captured. August 8, 2008

The maximum penalty for harming or killing a federally endangered species is currently $49,467. That does not include legal fees if you contest the fine in federal court. BLSG does not have the resources to cover such expenses, but fortunately for them, most of the towns in the BLSG District have just set the precedent of giving BLSG whatever it asks for to pay its attorneys.

So BLSG’s routine practices might be putting the taxpayers in the District towns at risk of legal expenses which dwarf the current legal bill of about $30,000 they just handed to the towns. One of the towns, Salisbury, will let the residents decide whether BLSG should get an additional $5,500 to pay its current lawyers. The Salisbury Town Meeting vote on March 5 includes an article that voters should consider carefully.

Cause and effect

There has been a lively recent discussion about mosquito control on the Front Porch Forum for Salisbury, Leicester, Ripton, and Goshen. A common observation made by local residents is that mosquitoes were once a terrible problem in the BLSG district, but since the BLSG-administered roadside spraying began years ago, the mosquitoes are not nearly as bad. The implication is that roadside spraying of chemical pesticides has been responsible for a long-term easing of the mosquito problem.

Evidence from this spring does not support that argument. The last time BLSG did roadside spraying anywhere in the district was June 8 which was 11 days ago when five routes were sprayed.  Nineteen days ago, another five routes were sprayed, and 21 days ago seven different routes were sprayed.  So as of today, all of the routes in the district have gone for at least 11 to 21 days without being sprayed.

The spray mist stops killing mosquitoes a few hours after the truck drives by. There is little or no long-term effect of this type of spraying because mosquitoes that weren’t flying or mosquitoes a couple hundred feet from the road are not affected. About 90% of the district is more than a couple hundred feet from a spray route, so most mosquitoes never encounter the pesticide. And it does little to stop new eggs from being laid or new larvae from hatching.

If it were the roadside spraying that keeps the mosquito population down and the district has gone 11 to 21 days without spraying, the mosquitoes should be as thick as they were back in the bad old days. But they are not. The mosquitoes are like they are most years in June–a minor nuisance at dusk and dawn just like they typically are everywhere else in Vermont this time of year.

If there is a long-term improvement in the mosquito situation it should not be attributed to roadside spraying of chemical pesticides. The cause might be natural variation in mosquito populations, or it might be the state-funded program of aerial larvicide application. That program prevents mosquito larvae from hatching into adults over thousands of acres of breeding areas and can have a substantial and long-term effect on the number of mosquitoes that residents experience. Our neighboring towns in the Lemon Fair Insect Control District use only larvicides to control mosquitoes.

The BLSG administration recently learned that they probably will not have enough money to apply the desired amount of larvicides during the next year. We should all be working to ensure that the Vermont Agency of Agriculture supplies adequate funding for this program. Unlike the chemicals sprayed along roads, the bacterial larvicides applied have trivial potential for health or environmental consequences.

The program of roadside spraying of chemical pesticides to kill adult mosquitoes is funded directly by the towns in the district. The last few weeks provide good evidence that this roadside spraying is not responsible for any long term or sustained reduction in the mosquito population. Select Board members in the towns of the BLSG district should think carefully about the tens of thousands of tax dollars being spent every year to repeatedly spray toxic chemical pesticides in residents’ front yards.  What evidence do you have that these dangerous chemicals aren’t doing more harm than good?

Comment on the Lemon Fair Insect Control District NOI

The two insect control districts in Vermont have submitted requests to continue their operations for the next five years. This request is referred to as a Notice of Intent (NOI) to apply pesticides according to Vermont’s Pesticide General Permit (PGP). The two districts are the Brandon-Leicester-Salisbury-Goshen-Pittsford Insect Control District (BLSG) and the Lemon Fair Insect Control District (LFICD) which includes Bridport, Cornwall, and Weybridge. The Vermont Department of Environmental Conservation (DEC) will make a decision about both NOIs very soon.

The Lemon Fair NOI was submitted recently and the public comment period is open until May 14. The LFICD controls mosquito larvae using the same bacterial larvicides as the BLSG. Unlike the BLSG, the LFICD does not also use methoprene, an insect growth regulator, to kill larvae. The LFICD does not do any roadside spraying of chemical pesticides (adulticides) to kill adult mosquitoes, while the BLSG has an extensive program of roadside spraying of permethrin and malathion to kill adult mosquitos.

We submitted a comment to the DEC and included six points which are summarized below. We are impressed with the LFICD’s plan to control mosquitoes without chemical pesticides. The LFICD confronts essentially the same mosquito problem as the BLSG, but unlike BLSG, LFICD recognizes that the environmental and health risks associated with pesticides like methoprene,  permethrin, and malathion might be more serious than the nuisance of some additional biting mosquitoes.

An outstanding question is: Can DEC approve two radically different plans to address the same mosquito problem?

1. The LFICD’s NOI correctly identifies its objective as controlling nuisance mosquitoes—not vector mosquitoes.

While recognizing that mosquitoes are potential vectors of arboviruses, the LFICD NOI does not attempt to justify its work with reference to serious, but locally rare diseases. In contrast, the BLSG’s NOI—currently pending review by DEC—frequently mentions mosquito borne illnesses, including some diseases that do not occur in Vermont, as their primary rationale for pesticide application.

According to Vermont Mosquito Control statutes, the jurisdiction to control vector mosquitoes lies with the Department of Health—not the BLSG or LFICD[1]. The Agency of Agriculture and Food Markets classifies the BLSG and LFICD as “nuisance” mosquito control districts.[2]

2. The District’s NOI is consistent with the intent of the Pesticide General Permit.

The LFICD’s philosophy and approach toward nuisance mosquito control is consistent with Vermont’s 2017 PGP and Integrated Pest Management (IPM). The PGP specifies that Operators should minimize the discharge of pesticides to waters of the State.[3] To accomplish this Operators are required to use Pest Management Measures, along with developing Action Thresholds, and a Pesticide Discharge Management Plan (PDMP), which deploys a Pest Management Options Evaluation—clearly specifying that pesticides are only to be used “if all other methods are unreasonable and have been exhausted.”[4]  In this case, the LFICD’s approach and practices demonstrate their efforts to minimize discharges of pesticides to surrounding waters. Specifically, the LFICD does not use chemical pesticides—unlike the neighboring BLSG. Rather, the LFICD uses only non-harmful bacterial larvicides.

3. The District’s Pesticide Discharge Management Plan is complete and well-structured.

The LFICD’s Pesticide Discharge Management Plan (PDMP), provided within their NOI, is well-structured, complete, and thorough. In particular, the PDMP accurately identifies a description of the Pest Management Area; the PDMP Team; Pest Problem Description—citing to nuisance mosquitoes, not vector mosquitoes; robust and detailed Action Thresholds; a Pest Management Options Evaluation; along with response procedures. Moreover, the provided Addendum regarding the District’s Action Thresholds in their PDMP fills in any gray areas that might arise upon reviewing the PDMP. But again, following a common theme throughout this comment, the LFICD’s PDMP stands in stark contrast to the BLSG’s PDMP that is currently under review.

4. The District’s Action Thresholds are robust and supported by sound data.

The synopsis provided in their Action Threshold addendum within the NOI demonstrates thoughtful consideration, context, and accuracy in developing a sound Action Threshold for biological larvicide application. Moreover, LFICD specifies that there must be over 10 dips representing a 200 acre area in order for the Action Threshold for larvicide application to be met. LFICD provided a thoughtful and complete explanation of the process and reasoning behind their action thresholds. In contrast, the BSLG’s NOI simply cited “10 per white dip cup” and “15 per trap/net sweep” with no context or justification. Not only does the LFICD include a higher Action Threshold (20 larvae per dip) for larvicide application than the BLSG (10 larvae per dip)—it’s thorough with the inclusion and requirement of over 10 dips representing a 200-acre area.

5. For the control of mosquito larvae, the District’s NOI proposes to apply bacterial larvicides, not the more widely toxic methoprene, an insect growth regulator.

The LFICD NOI specifies that they do not intend to use methoprene, an insect growth regulator, during their larvicide applications. This too, is consistent with the intent of IPM and the PGP of using the least harmful method for mosquito control. Again, this is in contrast to BLSG’s proposal in their recently submitted Notice of Intent, which outlines their intent to use methoprene without specifying how the dose will be determined—therefore leaving zero assurance that many aquatic invertebrates and vertebrates will not be harmed. Vernal pools—a critical habitat for vulnerable species (e.g., fairy shrimp, fingernail clams, amphibians)—are specifically targeted for application of methoprene in the BLSG NOI. We support the LFICD’s conservative approach to larvicide control, which poses minimal threat to wildlife.

6. The District proposes controlling nuisance mosquitoes without using harmful adulticide chemicals like malathion and permethrin.

Not only does this comply with the intent and philosophy of IPM, but it minimizes the discharge of pesticides to waters of the State of Vermont—a foundational aspect of the PGP. This approach lies in stark contrast with that of the BLSG. Specifically, mosquitoes in the LFICD region arise from same type of low-lying swamps and surrounding agricultural fields as in the BLSG. In fact, the town with the largest area of forested swamp (Cornwall Swamp) is located in the LFICD. Yet, the BLSG argues that roadside spraying of adulticides is a necessary part of their control method. We are not aware of any scientific evidence that mosquito density differs markedly between the two districts. Therefore, State’s approval of two radically different control strategies is both inconsistent and arbitrary. We applaud the past success of the LFICD in reducing mosquito populations without resorting to chemical pesticides, which have been proven to have deleterious environmental and health effects.

[1] See 6 V.S.A. §1083(6) (providing authority of the Secretary of Agriculture to issue permits “when the commissioner of health has determined that available information suggests that an imminent risk to public health exists as a result of a potential [disease] outbreak …)
[2] Mosquito Control Districts in Vermont,
[3] 2017 Vermont Pesticide General Permit, Section 3.1, Operator Responsibilities.
[4] 2017 Vermont Pesticide General Permit, Section 6.1.3, Pest Management Options Evaluation.

Where does BLSG spray to kill adult mosquitoes?

The BLSG Insect Control District sprays many miles of roads with a fog of pesticides to kill adult mosquitoes. You can learn if your property is on the mapped spraying routes at the BLSG website.

The road routes followed to spray pesticides to kill adult mosquitoes in Brandon. From the BLSG website.

Property owners in the insect control district can request that spraying not happen along their property. You must include a tax map when you submit your request that your property be a no-spray zone. For more information and to get a copy of the tax map of your property in Brandon, Leicester, Salisbury, Goshen, or Pittsford, visit our Google form. We will email you a free copy of your tax map.

Become a no-spray zone

The BLSG Insect Control District allows property owners along spray routes to request that no spraying be done along their property. To “opt out” you must mail a letter with your name and address and a copy of your property’s tax map. Letters must be sent by early April each year. If you would like a copy of your property’s tax map in Brandon, Leicester, Salisbury, Goshen, or Pittsford, submit your information at this Google form. MW&W will send you an email with an image of your parcel. Instructions for submitting your request are on the Google form.

This type of parcel map must accompany your request to opt out of spraying for adult mosquitoes. Click here to get yours.


Promoting a safe and healthy Moosalamoo region

Moosalamoo Woods & Waters is a local citizens group promoting safe and healthy environments in the Moosalamoo region of Addison and Rutland counties, Vermont.

We are residents of Brandon, Leicester, Salisbury, Goshen, and Pittsford which are in the BLSG Insect Control District. Sometimes mosquitoes are a serious nuisance in parts of these towns, so the state funds a quasi-municipal group to monitor and reduce mosquito larvae and to control adult mosquitoes along roads.

Our interests include answering questions about the biology of mosquitoes, the safety of pesticide spraying, and alternate methods of mosquito control.