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.

Salisbury balks at BLSG funding increase

In early January, members of the board of directors of the Brandon-Leicester-Salisbury-Goshen Insect Control District (BLSG) visited the select boards of each town in the District. They announced that they were asking for a large increase in the funds to operate in 2019-2020 compared to the previous year. The average increase requested was $7,443 per town for a total of $37,215 or 31% more than last year. They explained that the increase was primarily to pay their attorneys who are representing BLSG in a lawsuit.

The lawsuit is an appeal of the decision made by the state to authorize BLSG to spray pesticides under Vermont’s Pesticide General Permit. Details of the lawsuit are here:

One of the towns in the BLSG District did not accept the surprise request for more funds. Salisbury, which was asked for 46% more money than last year, instead budgeted for a small increase for BLSG and created an article on the Town Meeting ballot for additional money for attorneys. On March 5, voters in Salisbury can vote for or against $5,500 to pay BLSG’s lawyers.

The Salisbury Select Board was responding to strong opposition in the town to supporting BLSG’s legal troubles. Many residents thought that accepting BLSG’s request for 46% more funds than it needs for day-to-day operations was sending an inappropriate message to BLSG and to town residents. The Salisbury Conservation Commission wrote to the Select Board that “Salisbury should not be held financially responsible for the BLSG’s legal fees. Therefore, we urge the Select Board to level-fund the BLSG in 2019-2020 town budget.”

It seems to many that the primary effect of making more money available to lawyers would be to prolong the lawsuit because the lawyers will end the lawsuit whenever the money runs out. Voting against this article in Salisbury could encourage a quicker end to the lawsuit and avoid the establishment of a costly precedent.  

For more information on mosquito control in the BLSG District see the FAQ here:

BLSG lawsuit heads to trial

On February 4, the lawsuit involving the BLSG Insect Control District (BLSG) entered a new phase. Almost seven months after the case began, Judge Thomas Walsh of the Vermont Environmental Court was notified that the parties had been unable to reach a settlement agreement. The judge set a deadline of April 1 for the submission of preliminary motions as the case moves to trial.

The lawsuit was filed in June 2018 by Toxics Action Center who is represented by the Environmental and Natural Resources Law Clinic at the Vermont Law School. A month earlier, the Vermont Department of Environmental Conservation had authorized BLSG to spray pesticides under the State’s Pesticide General Permit (this permit allows the state to comply with the Federal Clean Water Act).

Toxics Action Center argues that the State should not have authorized BLSG to spray toxic pesticides because the documentation submitted by BLSG as part of the application process was incomplete. Vermont statutes are very clear about what an applicant must submit in order to be included under the state’s Pesticide General Permit. The lawsuit lists three required things that BLSG failed to include:

  1. BLSG failed to document how they evaluated the ways in which each of their mosquito management activities impacts water quality.
  2. BLSG failed to document how they evaluated the ways in which each of their mosquito management activities impacts animals and plants other than mosquitoes.
  3. BLSG failed to document how they minimize harmful discharge into waters by eventually resorting to chemical pesticides only if all other measures have been exhausted or are unreasonable.

These are not minor omissions from BLSG’s documentation. Vermont law requires anyone spraying toxic pesticides to be aware of the dangers their activities pose to the environment and human health and then to publicly document those dangers. By omitting these evaluations, residents of the BLSG District have no way of knowing whether no dangers exist, whether dangers exist and BLSG staff are not aware of them, or whether BLSG staff are aware of potential dangers but decided to downplay them.

We also don’t know why the state decided to authorize BLSG despite these gaps.  Both the state and BLSG are part of this lawsuit. If the case eventually makes it to trial, we will get answers to some of these questions.  

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?

Larvae or Adults

The BLSG Insect Control District operates two different mosquito control programs. The Vermont Agency of Agriculture funds a program to apply bacterial larvicide granules from the air to kill mosquito larvae in standing water. The five towns in the BLSG district fund a program to apply chemical pesticides along roads to kill adult mosquitoes.

The differences between the two methods of controlling mosquitoes are dramatic. Discussions about the effectiveness or safety of BLSG operations should specify which program is being discussed. The table below highlights some of the differences (click for better view).

This is a simplified outline of the two programs and many details are not included. For example, bacterial larvicides are not the only products used to kill mosquito larvae, and bacterial larvicides can be dispersed by hand. Also, spraying of chemical pesticides can be done via a backpack sprayer instead of a truck-mounted ULV machine.

Rare and rarer

There has been a lot of scary information about mosquito-borne diseases repeated by employees and board members of BLSG. There are two serious diseases carried by mosquitoes in Vermont, and one killed two people in 2012. That fact alone deserves our attention, but how much should we be concerned about these diseases?

According to available CDC data (pre 2016), since West Nile virus first appeared in Vermont in 2011, eight people in the state have become ill from the virus, and we assume they contracted it from mosquito bites. Since 2011, only two people have gotten sick from Eastern equine encephalitis, both in 2012. Tragically, those two people died from the disease.

That is a total of 10 cases of mosquito-borne disease in Vermont. These two diseases are terrible, but they are both rare in the state.  Most healthy people who get infected with these diseases have flu-like symptoms and recover in a few weeks.

To put the risk of these diseases in perspective, they are both much rarer in Vermont than some other diseases that most of us never think about.  In Vermont, we are 10 to 100 times more likely to contract tuberculosis, Legionnaires’ disease, or Cryptosporidiosis (whatever that is) than to get eastern equine encephalitis.  We are four to 40 times more likely to get those potentially deadly diseases than to get West Nile virus.

The risk of contracting three uncommon diseases in Vermont compared to contracting two mosquito-borne diseases in Vermont. Mosquito-borne diseases are very rare in Vermont compared to these three diseases that most of us never think about. We are five to 100 times more likely to get tuberculosis, Legionnaires’ disease, or Cryptosporidiosis than to get either mosquito-borne disease.   Data from CDC. 

Knowing the true risks of mosquito-borne diseases in Vermont helps us make sound decisions about how to protect ourselves from them. Repeated and alarming rhetoric about these very rare diseases could cause more harm than good, especially when it encourages us to ignore the risks of regular doses of pesticides which are known to have potential health risks. Many people in the BLSG district are very concerned that the chances of being harmed by roadside spraying of toxic pesticides are far greater than the chances of ever getting a disease from a mosquito.

It is especially disturbing that BLSG continues to name Zika virus as a disease we should be concerned about in Vermont. No one in the US has ever gotten Zika virus from a mosquito north of Texas and Florida. You won’t learn that from the scary information at the BLSG website or their forays into the local newspapers.

Before we make decisions about whether to invite exposure to neurotoxins like malathion and permethrin we should understand the true risks of nuisance mosquitoes.

Toxics Action Center appeals the BLSG’s permit approval

One month ago, the Vermont Department of Environmental Conservation (DEC) approved an application by the BLSG Insect Control District to continue controlling mosquitoes for another five years. Yesterday, that decision was appealed by Toxics Action Center, an environmental advocacy group working throughout New England. The lawsuit alleges that the Vermont DEC allows BLSG to spray pesticides without following state requirements designed to protect public health and the environment. Toxics Action Center initiated this legal action on behalf of its members in the region. “It’s irresponsible to allow toxic pesticides to be sprayed near homes, rivers, and farms while safer options are available,” said Woody Little, Vermont Community Organizer at Toxics Action Center. “Before we endanger the health of the community, we should be trying every non-harmful alternative possible. It’s the law, and it’s just common sense.”

Toxics Action Center will be represented in front of the Environmental Division of the Vermont Superior Court by the Environmental & Natural Resources Law Clinic at Vermont Law School. “The spraying authorized by the DEC violates state and federal laws designed to protect human health, water quality and endangered species,” said Mason Overstreet, an attorney and fellow at the Environmental & Natural Resources Law Clinic. “The law requires the District to use non-harmful alternatives whenever practical. Chemical pesticides should only be used as a last resort.”

Under the federal Clean Water Act and state law, insect control districts must comply with Vermont’s National Pollution Discharge Elimination System Pesticide General Permit for application of pesticides. An entity applying for a permit to spray pesticides is required to minimize the discharge of chemical pesticides and consider the impacts on water, insects, and animals before using chemical pesticides. The pending lawsuit addresses whether gaps in BLSG’s application suggest that BLSG could avoid these requirements without consequences. You can read today’s press release from Toxics Action Center here.

Details of the legal complaint will be submitted to the court in about three weeks. Operations of the BLSG to control mosquitoes will likely continue while the appeal proceeds. You can stay up-to-date with their spraying activities and other news on Twitter and Facebook (see sidebar).

Permanone is in the air

This week the BLSG started roadside spraying of pesticides to kill adult mosquitoes. Pesticide application is now being done under Vermont’s 2017 Pesticide General Permit after the Department of Environmental Conservation approved, on May 15, the BLSG request to continue operation.

We will be announcing, whenever possible, the dates and location of roadside spraying of adulticides in the district. The best way to get advance notice is to follow us on Twitter or Facebook (see the right sidebar).  We might also be able to send alerts by text or email, so let us know if you would be interested in that.

The pesticide being sprayed tonight is Permanone which is a formulation containing about 4% permethrin. Here is the active ingredient list from the label posted by BLSG:

Permethrin………………………………………….. 3.98%
Piperonyl Butoxide* ……………………………. 8.48%
OTHER INGREDIENTS†…………………….. 87.54%
TOTAL: 100.00%
* (butylcarbityl)(6-propylpiperonyl) ether and related compounds.
† Contains petroleum distillate

Piperonyl butoxide is a synergist which works by inhibiting the natural defense mechanisms of the insect. It is not a pesticide, but makes the permethrin more deadly.

Here is what the label says about the environmental hazards of Permanone:

ENVIRONMENTAL HAZARDS This pesticide is extremely toxic to aquatic organisms, including fish and invertebrates. Runoff from treated areas or deposition of spray droplets into a body of water may be hazardous to fish and aquatic invertebrates.

Before making the first application in a season, it is advisable to consult with the state or tribal agency with primary responsibility for pesticide regulation to determine if other regulatory requirements exist.

Do not apply over bodies of water (lakes, rivers, permanent streams, natural ponds, commercial fish ponds, swamps, marshes, or estuaries), except when necessary to target areas where adult mosquitoes are present, and weather conditions will facilitate movement of applied material away from the water in order to minimize incidental deposition into the water body. Do not contaminate bodies of water when disposing of equipment rinsate or washwaters.

This pesticide is highly toxic to bees exposed to direct treatment on blooming crops or weeds. Do not apply this product or allow drift when bees are actively visiting the treatment area, except when applications are made to prevent or control a threat to public and/or animal health determined by a state, tribal, or local health or vector control agency on the basis of documented evidence of disease causing agents in vector mosquitoes, or the occurrence of mosquito-borne disease in animal or human populations, or if specifically approved by the state or tribe during a natural disaster recovery effort. Applications should be timed to provide the maximum possible interval between treatment and the next period of bee activity.

The entire label for Permanone is at the BLSG site.

We hope the guys preparing and driving the spray trucks stay safe.


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.

What’s in the CDC report for Vermonters?

Every week, the Centers for Disease Control and Prevention (CDC) releases a report on diseases, and last week’s report was about the rise in diseases spread by insects and ticks. This was a typically dry and technical report about trends between 2004 and 2016 in human cases of 16 diseases spread by ticks, mosquitoes, and fleas. The CDC also publicized this report at their Vital Signs site where the hype was cranked up by a dramatic video and some revealing graphs.

The story was picked up by many major news outlets (Chicago Tribune, New York TimesForbes, Boston Herald, CNBC) under scary headlines like “Diseases spread by ticks, mosquitoes and fleas more than tripled in the U.S.”

Should Vermonters be alarmed by this report?

For Vermonters, a primary message of the CDC report is: If you want to be concerned about a vector-borne disease in Vermont, be concerned about Lyme disease. For the last decade, the probability of contracting Lyme from a tick bite in Vermont has been at least 100 times greater than contracting any disease from a mosquito. Between 2004 and 2016, annual cases of Lyme in Vermont increased from 50 to 761, and the CDC suggests that additional unreported cases might increase those numbers tenfold. Vermonters should learn about Lyme disease and know how to avoid it.

There has not been a similar increase in the number of cases of mosquito borne diseases in Vermont. The first cases of West Nile virus (WNV) and eastern equine encephalitis (EEE) in Vermont were in 2011 and 2012 respectively. There have been a total of only two cases of EEE in Vermont and eight cases of WNV, and there is no indication that the number of cases is increasing.

The headlines highlighting a “tripling” of diseases in the US are accurate only if you include Puerto Rico. That’s because Puerto Rico tragically suffered some 40,000 cases of Zika in 2016. This spike is evident in the two graphs below.

Above: The big number of cases in 2016 is due to 40,000 cases of Zika in Puerto Rico. The rise elsewhere in the US is not so striking (Zika is not transmitted by mosquitoes in the US north of Florida and Texas).  Most of the cases included in the graph above are tick-borne, not mosquito-borne. Source.


Above: This is the same data as in the previous figure. Most of the cases included in the CDC report are tick-borne diseases (light blue). The outbreak of Zika in Puerto Rico in 2016 is represented by the large medium blue bar in 2016. Note the relatively small number of cases of mosquito-borne diseases in US states (dark blue) and the modest increase over time since 2004. Source.

The CDC report cites a 2017 study of local organizations, including insect control districts, that are responsible for controlling disease vectors. Many of these organizations are chronically underfunded, and most of them are lacking in at least one core competency required to effectively protect the public. The most common shortcoming was testing for insect resistance to the pesticides applied. Making reliable surveys of insects was the third most common shortcoming, and basing treatment decisions on those surveys came in second.

Above: The local organizations tasked with controlling disease vectors are lacking at least one core competency. Source.


Although cases of Lyme disease have seen a steady increase over 13 years, mosquito-borne diseases like WNV and EEE are more prone to short term outbreaks, often followed by many quiet years. Scientists are not able to predict the outbreak years, so monitoring for the presence of WNV and EEE in mosquitoes is critical. When the next big year happens in Vermont, we hope the Vermont Department of Health is up to the task.

Pretty good press

Moosalamoo Woods & Waters was in the local paper last week. Lou Varricchio from the Addison Eagle and True North Reports asked two of our members some questions about mosquitoes, larvicides,  and pesticides. Chris Fastie and Wally Bailey are both quoted in the article. Will Mathis of the BLSG Insect Control District is also quoted, although those quotes were from an essay in the Rutland Herald authored by Mathis. Reporters have not had much luck this spring arranging interviews with BLSG members.

Varricchio asked good questions and quickly grasped the position of Moosalamoo Woods & Waters. Unfortunately, he included one very misleading statement from Will Mathis:

” Even a case of mosquito-borne Zika virus, …, has been reported in Vermont.”

It is true that in 2016 one Vermonter contracted the Zika virus, but it was not as a result of a mosquito bite in Vermont. The patient had travelled to an area where Zika is transmitted by mosquitoes. No one north of Texas and Florida has ever contracted Zika from a mosquito. The primary vector mosquito for Zika does not live as far north as Vermont. If a reporter ever gets to talk to someone from BLSG, it would be good to ask why they continue to mislead the public about the risk of contracting Zika from a mosquito in Vermont. Today, that risk is zero.

One of BLSG’s stated goals is public education about mosquitoes. They are not achieving that goal when they repeat misleading information about such an important topic.

Aedes vs. Aedes

A new approach to mosquito control is being widely deployed for the first time this year. A commercial product called the In2Care Mosquito Trap is being tested around the world to control Aedes mosquitoes which carry several tropical diseases.

The trap attracts certain mosquitoes, infects them with larvicide and fungus, and allows them to escape and contaminate natural breeding sites with larvicide. The fungus eventually kills the contaminated mosquito.

This trap is designed primarily for Aedes mosquitos which are rare in Vermont. Someday this concept could be applied to other species.

Methoprene and vernal pools

Thursday’s Rutland Herald article by Will Mathis, Director of Operations of the BLSG Insect Control District, focused on the larvicide program. Although the article was titled “Mosquito spraying program explained,” no mention was made of malathion or permethrin which are sprayed along town roads to kill adult mosquitoes. Instead, the article focused on the program to treat standing water to kill mosquito larvae before they hatch.

The major effort of the larvicide program is spreading bacteria from a helicopter over the Otter Creek floodplain swamps and fields. The two bacteria used (Bacillus thuringiensis israelensis, and Lysinibacillus sphaericus, until recently known as Bacillus sphaericus) contain toxic crystals which are activated by conditions in a mosquito larva’s gut and kill the larvae. These bacteria have shown no toxicity to people or animals other than mosquitoes and a couple of other types of small flies. Well-timed application of these bacteria can dramatically reduce the number of certain species of mosquitoes.

Not all mosquito species breed in floodplain swamps and fields, and helicopter application cannot efficiently target many dispersed small pools. So another type of larvicide, methoprene, is applied by hand to some water bodies. Methoprene is not a bacteria, it is an insect growth regulator. Insect larvae exposed to it never metamorphose into adults. Methoprene is not specific to mosquitoes and interrupts the development of many aquatic insects and other invertebrates. Mosquitoes are very sensitive to methoprene, so if its concentration in water is low, the primary toxicity will be on mosquitoes and some other small invertebrates.

A vernal pool in the Salisbury Town Forest. April 29, 2009

The loss of some harmless non-target creatures might be an acceptable price to pay for controlling mosquitoes, unless those creatures are part of a critical ecosystem. Vernal pools are small temporary ponds that are wet just long enough in the spring to support ephemeral populations including amphibians, fingernail clams, and fairy shrimp. Amphibians hop or crawl away before the pools dry up, but the clams, fairy shrimp, and other invertebrates persist for months until the pools fill up again. There is not much data on how these invertebrates tolerate methoprene, but vernal pool communities are sufficiently valued that it might be wise to avoid the risk of serious disturbance. Some authorities have banned the use methoprene in vernal pools, for example in a California mosquito control district “Because of the effects of methoprene on fairy shrimp and a lack of information on how long the agent remains in the soil, use of the larvicide methoprene within vernal pools or swales at any time, in either wet or dry conditions, is prohibited.”

It will be good to learn more about where methoprene is used in the BLSG district, and how the concentration of methoprene is kept low enough to affect only mosquitoes and other small invertebrates.


BLSG doubles down on Zika scare tactics

There is some very useful information in yesterday’s Rutland Herald article by Will Mathis, Director of Operations of the BLSG Insect Control District. So it was disappointing to see the group is still misleading residents about the risk of contracting the Zika virus from mosquitoes in Vermont. The article mentions that insect borne diseases are part of their justification for controlling mosquitoes, and then adds “Vermont has now recorded its first case of the Zika virus.”

The Vermonter with Zika did not get it from a mosquito bite in Vermont or anywhere north of Florida or Texas. That Vermonter had travelled to an area where Zika is present. Zika virus and the primary mosquito vector of the disease (Aedes aegypti) are not present in Vermont (more here).

Vermont residents need to make important decisions about reducing the risks of mosquito borne diseases. Suggesting that Vermonters should be concerned about a disease that is not carried by mosquitoes here is counterproductive. The BLSG website also exaggerates the importance of Zika with a scary five-page “special report” about it. This seems like an irresponsible approach to public education.

Updated BLSG policy on opting out of roadside spraying

Yesterday’s Rutland Herald article by Will Mathis, Director of Operations of the BLSG Insect Control District included new information about requesting that no pesticides be sprayed along private property in the district. Last week, BLSG published notices in the local newspapers that insect control operations will happen this year, and that landowners could request that their property be a “no spray zone.” Similar details about the opt-out program are posted at the BLSG website.

In yesterday’s article, very different rules were described. Instead of a deadline of “early April” for making your request, the article states that “We will accept and process requests anytime during the season.”

Instead of requiring that a letter and property map be mailed to BLSG, the article states that “Any citizen can opt out by calling 247-6779.”

These are welcome changes because they make it easier for landowners to opt out of spraying, and make it possible for new residents arriving in the summer to opt out.

When a resident opts out of roadside spraying, it creates some extra work for BLSG staff. The property boundaries must be marked along the road with “stop and start” stakes, which must be removed at the end of the season. Learning where these stakes should be installed often requires meeting with the landowner at the property.

We encourage landowners who plan to opt out to do so before early April so the BLSG staff has time to mark the properties before the mosquito season gets underway. We are just about at the end of early April, so if you have been considering opting out, this might be a good time. More information about opting out is here.

Vermont DEC wants clarification about BLSG’s pesticide plans

A new article posted by the Rutland Herald today reports that the Vermont Department of Environmental Conservation has asked for more information about the BLSG Insect Control District’s application to apply pesticides to control mosquitoes. “I just asked them to clarify some pieces of their pesticide discharge management plan,” said Misha Cetner of Vermont DEC.

The article also reported that Mason Overstreet of the Environmental and Natural Resources Law Clinic at Vermont Law School has asked the state to deny the permit. “We see their application as deficient,” Overstreet said of the BLSG permit request. “We are concerned that the district has arbitrary action thresholds.”

The DEC is expected to make a decision on the BLSG permit in the next month.

We have been introduced to Rutland

The Rutland Herald posted an article today about Moosalamoo Woods & Waters. Staff Writer Susan Smallheer talked to a few of us and then described our new group and our current project of providing property maps to landowners in the BLSG Insect Control District who want to opt out of roadside pesticide spraying along their property.

Malathion or permethrin are sprayed along town roads during the warm months to kill adult mosquitoes. To opt out of spraying along your property, you must mail a letter with a map of your property to BLSG. We will email you a property map for this purpose (see instructions here).

The BLSG website states that opt out letters must be mailed by “early April” every year, so there is not much time left. Today’s Rutland Herald article stated that letters should be sent before May 15, but that is when the spraying might start, so I think the time to opt out is right now.

Where is Zika?

There was a lot of news about Zika virus two years ago when 17 athletes, including four top seeded golfers and some big tennis stars, pulled out of the 2016 Rio Summer Olympic Games ostensibly over Zika fears. The Zika story fizzled after the games, although some athletes later tested positive for antibodies to other arboviruses.

In the US, Zika can be transmitted by mosquito bites, but according to the CDC, there is “no known Zika” from mosquitoes outside of Florida and Texas.

Zika has been present in mosquitoes in Florida and Texas, but not in any other state. Source.

Zika is thought to be transmitted by only two species of mosquitoes (Aedes aegypti and A. albopictus) which are rare or absent in New England. In 2016 and 2017, the Vermont Agency of Agriculture, Food & Markets monitored for A. albopictus and failed to find any. Populations of A. aegypti have apparently never been present in Vermont.

The Aedes mosquitoes which transmit Zika are either “very unlikely” or “unlikely” to live and reproduce in Vermont. Source

Although there is no reason for concern about exposure to mosquito-borne Zika in Vermont, The BLSG website has a page titled “Information Center for Zika, EEE, and WNV.” It is important to monitor Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV) in Vermont, and we should all be aware of the level of risk associated with those arboviruses. On the BLSG website, more space is dedicated to Zika than to EEE and WNV combined. This is rather misleading to local residents trying to make decisions about staying safe from mosquito-borne diseases, and does not inspire confidence in other information provided by the BLSG district.

A comment from Dr. Lawton

A few reader comments were generated by the VTDigger article about the imminent DEC decision on the BLSG Insect Control District’s permit to operate. The full verbatim text of a comment by Dr. Benjamin Lawton, the chair of the BLSG, follows with some comments.

Ben Lawton’s (B.L.) comment in italics, our response in blue.

B.L. I have some additions and corrections to the article on mosquito control first notices of intent to apply insecticides are posted at the town clerks offices in the local newspapers and through public service announcements and on our website

Residents would like to be alerted whenever spraying happens on their road. This would allow them to take the actions recommended by the EPA if they are concerned about exposure to pesticides (e.g., for malathion: closing windows, bringing in children’s toys, covering gardens). Could the BLSG district send an email to a few people who can announce (e.g., via social media) that an action threshold has been reached and spraying will occur that evening?

B.L. Any citizen can opt out of adulticiding and their property boundaries will be posted as a no sprays zone !!!

The BLSG website states that pesticide spray from the truck can drift up to 150 feet from the truck. When someone opts out of spraying along their property, does the truck stop spraying 150 feet from that property and start again only when the truck is 150 feet past the property? If this does not happen, isn’t it true that a resident cannot really opt out of exposure to pesticides?

B.L. The district uses ultra low volume applications (the minimum affective volume of a pesticide) against the flying adult mosquitoes. Both ground and Ariel ULV Applications have been the standard method of mosquito adulticiding World wide for more than 45 years

( by the way, the mosquito is the most deadly organism known to man. !)

Technically, mosquitoes have not killed anybody. Several different arboviruses and other microorganisms carried by mosquitoes have killed many. Millions of people have contracted these diseases, most of which ( malaria, yellow fever, Chikungunya, dengue fever, filariasis, Zika virus) are not present in mosquitoes in Vermont.

B.L. The optimum size droplet for mosquito control with field applied ground ULV has been determined to be 5 to 25 µm which is optimal for truck Based sprayers!

This contradicts published studies. Optimum droplet size for effective (≥90% mortality) mosquito control by space spraying via ground application equipment is 8–15 μm (Mount 1998), while a slightly larger droplet size (5-25 μm VMD) is most effective when applied by aerial methods (Mount et al. 1996).

Mount, G. A. 1998. A critical review of ultralow-volume aerosols of insecticide applied with vehicle-mounted generators for adult mosquito control. J Am Mosq Control Assoc 14:305–334.

Mount, G. A., T. L. Biery and D. G. Haile. 1996. A review of ultralow-volume aerial sprays of insecticide for mosquito control. J Am Mosq Control Assoc. 12(4):601-18.

B.L. The ultimate goal is targeted applications with minimal nontarget exposure. Other flying insects do not appear to be affected by mosquitocidal sprays if their body mass is larger than that of a mosquito .

So a small nocturnal mayfly, caddisfly, beetle, or moth can fly through the white cloud sprayed by the truck and be unharmed? What published study suggests that non-mosquito insect species are not harmed by the spray? In those studies, how many species are harmed?

B.L. (Lawler etal 2008,Jensen etal 1999) Found non-detectable concentrations of Pyrethrins and permethrin In water samples from wetlands, before and after truck mounted ULV applications.

I have not been able to find the Lawler or Jensen articles cited above, but other work by these same authors demonstrate the severe effect of pyrethrin, malathion, or permethrin on small insects and other arthropods. For example:

“… significantly (P< 0.001) higher diversity and numbers of nontarget arthropods were found dead on tarps in the treatment sites versus the Davis and non-Davis control sites (Table 2). All of the dead nontarget species were small-bodied arthropods belonging to >25 families in the following orders: Blattodea, Coleoptera, Collembola, Diptera, Hemiptera, Hymenoptera, Psocoptera, Thysanoptera, Acari, and Araneae.”

The orders listed include beetles, springtails, flies, bugs, bees and wasps, thrips, mites, and spiders.

Source: Nontarget effects of the mosquito adulticide pyrethrin applied aerially during a West Nile virus outbreak in an urban California environment. Walter M. Boyce, Sharon P. Lawler, Jennifer M. Schultz, Shannon j. Mccauley, Lynn S. Kimsey, Michael K. Niemela, Carrie F. Nielsen, and William K. Reisen. Journal of the American Mosquito Control Association 2007 23 (3), 335-339

B.L. Results from risk assessments (Schleier etal2009 ,Peterson’s etal2006) and the current weight of scientific evidence indicates that human health risk from residential exposure to mosquito insecticide are low and not likely to exceed levels of concern!

What does it mean that “health risk” is not likely to “exceed levels of concern?” This suggests that there is some health risk, so the above statement is false if there is not much concern. Does that mean that many people in the BLSG district are concerned about pesticide spraying?

Both of the articles cited are modelling studies. Creating the models required that someone assign relative importance to exposure to pesticides and to contracting a disease. No actual data were collected on the consequences of spraying or the consequences of mosquitoes on actual humans.

One of the authors of Schleier et al. 2009 worked for ICM Ventures, Fort Collins, CO. which might have been a petrochemical-related company.

Schleier et al. 2009    

Peterson et al. 2006

B.L. Furthermore, the results indicate that, based on human health criteria, the risk from west Nile virus and equine encephalitis exceed the risks from exposure to mosquito insecticide!

It is not clear what “human health criteria” are, but this does not seem to say anything different from the last statement.

B.L.  In 2012 there were two deaths from EEE In the local towns transmitted by mosquitoes!!!!!

From 2007 to 2016, the average annual incidence of EEE in Rutland County was less than one case per 200,000 people. In Addison County, the 10-year average was zero. This seems like an exceedingly small risk of contracting the disease. In that 10 year period, 2012 was the year of highest incidence of EEE in the US, and it has been much lower since then.

Has anything changed in the operations of the BLSG Insect Control District since 2012 that suggests that those operations will now protect residents from mosquito-borne diseases?

This map shows the distribution of Eastern equine encephalitis virus neuroinvasive disease (encephalitis and/or meningitis) average annual incidence by county of residence from 2007 through 2016. Counties are shaded according to incidences ranging from less than 0.20, 0.20 to 0.49, and greater than 0.50 per 100,000 population. Shaded counties are primarily distributed along the Gulf Coast, Eastern seaboard, and the Great Lakes. Map source:

B.L. BLSG has been providing mosquito control since 1987 to the area town’s. Unfortunately many of the newer residents of the area have not experienced the clouds are mosquitoes that once infested the area prior to initiating control !!!!!

This is a very important result. The former Vermont State Entomologist, Alan Graham, counted adult mosquitoes in the BLSG district during 1989 and in most years since 2001. I assume that is the source of the information you are referring to. It would be good to see Alan Graham’s report on the long-term trend in mosquito population density in these towns. I am not aware of population data from earlier years so there might be no scientific evidence of your suggested longer term changes in mosquito density. If there is no verified trend in mosquito populations, then there is no basis for inferring any effect of insect control treatments on those populations. If adult mosquito populations have declined over the years because of control measures, this could be due to larvicide treatments which are not a source of concern for residents. Residents are concerned about malathion and permethrin being sprayed along town roads.