Who grants permits to spray mosquito pesticides?

According to a new article by Vermont Digger, The BLSG Insect Control District does its work under the auspices of two different Vermont agencies. The Agency of Agriculture and Food Markets grants permits to both of Vermont’s insect control districts to apply larvicides on standing water to kill mosquito larvae. Although the Agency of Agriculture and Food Markets grants permits to apply many types of agricultural chemicals, it does not regulate the spraying of pesticides like malathion and permethrin to kill adult mosquitoes. It does train and license operators who spray these pesticides, but no permit is required. Instead, a Vermont insect control district must be approved by the Department of Environmental Conservation (DEC) to spray pesticides to control adult mosquitoes. In order to spray pesticides, an insect control district must obtain a Pesticide General Permit (PGP), a type of National Pollutant Discharge Elimination System (NPDES) permit, and comply with the provisions outlined in the PGP.

The Agency of Agriculture’s agrichemical management chief, Cary Giguere, said the Agency is likely to begin drawing up adulticide regulations this summer. Until new regulations are implemented, how the BLSG district sprays adulticides will be determined by the imminent decision of the DEC.

In advance of the DEC decision, a meeting is planned for March 27 to discuss these jurisdictional issues. Officials from DEC, Agency of Agriculture, and Vermont Law School’s Environmental and Natural Resources Law Clinic will be present at the meeting.

West Nile virus in Vermont

Avoiding mosquito-borne diseases like West Nile virus is a primary motivation for mosquito control. Since it was first confirmed in the US in 1999, West Nile virus has infected more than 46,000 people in the US and more than 2,000 people have died. Mosquitoes infected with West Nile virus have been found in every Vermont county in past years, so this threat should not be ignored. However, between 1999 and 2016, only 12 cases of West Nile virus were reported in people in Vermont (Figure 1).

Figure 1. Total number of cases (mild plus neuroinvasive) of West Nile virus in US states (1999-2016) ordered from most (left) to least (right). Source.

New England has a comparatively low per capita incidence of West Nile virus disease. Between 1999 and 2016, the chance each year of developing a serious disease from West Nile virus was zero in most Vermont counties, and less than 1 in 200,000 in Addison County (Figure 2).

Figure 2. Average annual incidence (1999-2016) of neuroinvasive disease caused by West Nile virus by county. Source.

These results suggest that monitoring the presence of West Nile virus in Vermont is important, but alarming rhetoric about the disease risk in Vermont might not be justified.


Why so many mosquitoes?

Eight towns in Vermont have formed insect control districts to monitor and reduce mosquito populations. Five towns are in the BLSG district, and Cornwall, Weybridge, and Bridport are the Lemon Fair Insect Control District. These contiguous towns are all in Addison or Rutland counties in the Champlain Valley.

Both districts apply a biological larvicide to standing water to kill mosquito larvae. Only the BLSG district also sprays a mist of pesticide along roads to kill adult mosquitos. The extra effort might be justified by the extra mosquitoes which breed in the extensive floodplain swamps and fields along Otter Creek. The central part of the Otter Creek valley is so flat that it is more like a plain than a valley. In the 30 miles between Rutland and Middlebury, Otter Creek drops only 165 feet in elevation. If you follow the wandering course of the creek, you might drop only four feet per mile. The broad, flat swamps and fields along the creek are under water during most springs, and that standing water can allow a lot of mosquitoes to breed.

The colored part of the map is in the watershed of Otter Creek. Salisbury, Leicester, and Brandon hug the huge, flat Otter Creek floodplain (green) where mosquitoes breed. Pittsford includes a narrower section of the floodplain. One of these five towns is not like the others.

Brandon, Leicester, and Salisbury formed the first insect control district in 1979. The map above suggests why mosquitoes might have always been such a nuisance there–a lot of flat floodplain is in and near those towns. Goshen has been a member of the district since 1990, and Pittsford fully joined only this year. Goshen is far from the Otter Creek floodplain and well above the swampy valley floor, so it’s not obvious why it joined the district while Ripton and Chittenden (north and south of Goshen) have not.

Pittsford votes to become a full member of the BLSG Insect Control District

The town of Pittsford, Vermont voted at town meeting on March 6, 2018 to become a full member of the BLSG Insect Control District. For the first time, spraying will be done along town roads in Pittsford to kill adult mosquitoes.  The measure passed by a vote of 35 to 24.

Pittsford joined the BLSG district in 2016 and has participated in the application of larvicide to lowland areas to kill mosquito larvae. Before then, Pittsford contracted with the BLSG for larvicide application.

According to an article in the Rutland Herald, Pittsford will be paying more than $40,000 in each of the next four years to cover the treatments and contribute to the BLSG infrastructure.

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.

Permethrin factsheet

The BLSG Insect Control District sprays pesticides along town roads to kill adult mosquitoes. The most recent public notice from the District identifies the pesticides as “malathion or synthetic pyrethroid insecticides.” Permethrin is the most commonly used synthetic pyrethroid. It is considered to be much less toxic to humans than malathion, and is sometimes less effective for controlling mosquitoes. The equipment used by the BLSG to spray permethrin produces tiny droplets so a very small amount of chemical is needed. Nonetheless, permethrin is toxic to organisms other than mosquitoes. A factsheet on permethrin from the group Beyond Pesticides includes human health precautions about cancer, immune system effects, and effects on reproduction.  Here is a link to the fact sheet which includes citations of the studies on which it is based: https://beyondpesticides.org/…/pe…/factsheets/permethrin.pdf

Pesticide manufacturers and distributors are required to include specific precautions in the labels on their products. This is the label for a product containing permethrin. It states “Avoid breathing vapors or spray mist. … Do not use on humans.”

EPA’s guidance for reducing exposure to malathion

There is a lot of information available about the pesticides used in the BLSG Insect Control District. The most recent public notice from the District identifies the pesticides as “malathion or synthetic pyrethroid insecticides.” On the EPA’s mosquito control website, the page about malathion suggests that “people who are especially concerned may choose to take some of these steps to help reduce exposure”:

1. Stay indoors with the windows closed.
2. If you are outdoors during spraying operations and you can see the spray, avoid contact with it. If you can’t avoid contact, rinse your skin and eyes with water.
3. Wash fruits and vegetables from your garden before storing, cooking or eating.
4. Cover outside items like furniture and grills while the spraying is occurring. Bring pets and items like pet food dishes and children’s toys indoors
5. If you think you have had a reaction to the mosquito spray, talk to your doctor or call the regional Poison Control Center at 1-800-222-1222.

EPA’s information on Malathion is here: https://www.epa.gov/mosquitocontrol/malathion

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.


The BLSG district

The BLSG Insect Control District includes the towns of Brandon, Leicester, Salisbury, Goshen, and Pittsford. We are not the only insect control district in Vermont, but we are the only one where pesticides are sprayed to control adult mosquitoes. In addition to treating many acres of standing water to kill mosquito larvae, malathion or permethrin are sprayed in a fine mist from a slow moving truck along some town roads.

Below is a map of the five towns currently in the BLSG district.

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.