Bti for Mosquito Control

Good advice on larviciding from the US EPA. It’s so much easier to get rid of larvae that can’t escape than winged adults that fly where they wish! And right now is the time to dispatch all possible larvae, before numbers start to multiply.

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1. What is Bti?

Bti is a biological or a naturally occurring bacterium found in soils. (Bti is short for Bacillus thuringiensis subspecies israelensis.) It contains spores that produce toxins that specifically target and only affect the larvae of the mosquito, blackfly and fungus gnat. EPA has registered five different strains of Bti found in 48 pesticide products that are approved for use in residential, commercial and agricultural settings primarily for control of mosquito larvae.

2. Does Bti pose health risks to humans?

No. Bti has no toxicity to people and is approved for use for pest control in organic farming operations. It has been well tested by many studies on acute toxicity and pathogenicity (ability to cause disease) for Bacillus thuringiensis including studies specifically on Bti. Based on these studies, EPA has concluded that Bti does not pose a risk to humans.

3. Where has Bti been used for mosquito control?

Bti is used across the United States for mosquito control. Bti is approved for aerial spraying, which has taken place in Massachusetts, Pennsylvania, Maryland and Michigan, among other states. Bti can be sprayed over waterbodies such as ponds, lakes, rivers and streams. Bti is used to kill developing mosquito larvae by being applied to standing water where those larvae are found. Bti can be used around homes in areas and containers where water can collect, such as flower pots, tires, and bird baths. Bti can also be used to treat larger bodies of water like ponds, lakes and irrigation ditches.

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4. Will Bti work to control mosquito larvae?

Yes, Bti has been shown to be effective in reducing mosquito larval populations and could be effective in controlling mosquitos carrying Zika, dengue and chikungunya in places like Puerto Rico and other areas where these diseases have been identified.

5. Are insects becoming resistant to Bti?

No. There is no documented resistance to Bti as a larvicide. A recent study (Tetreau et al. 2013) confirmed previous research showing a lack of Bti resistance in mosquito populations that had been treated for decades with Bti.

6. Are there special precautions to be taken during Bti spraying?

No special precautions are needed for applying Bti. A number of Bti products are sold as “homeowner” products and are easy and safe to use. People do not need to leave areas being treated. However, as is the case with many microbial pesticides, some commercial use Bti products may require applicators to wear a dust/mist filtering mask.

7. How will I know if aerial spraying is going to take place?

Decisions about where and when to spray will be made by local officials. Listen for announcements in your community with the dates, times and locations of upcoming sprayings on social media sites, newspapers or radios.

8. Does Bti pose risk to crops or water supplies?

No. Bti has no toxicity to people, so it can be applied safely to mosquito habitat without a detrimental impact on food crops or water supplies. In fact, Bti can be used for pest control in organic farming operations. It is important to follow the label for any Bti product to ensure that the product is being used correctly. There are multiple Bti products and some are allowed to be used on certain drinking water (e.g., cisterns) while others are not intended for that use.

9. Is Bti harmful to wildlife including honey bees?

Studies indicate Bti has minimal toxicity to honey bees. Bti produces toxins that specifically affect the larvae of only mosquitoes, black flies and fungus gnats. These toxins do not affect other types of insects including honey bees.

10. Is there a medical test to show whether I’ve been exposed to Bti?

Since Bti has no toxicity to humans, a medical test to show exposure to the active ingredient has not been developed.

11. What other measures should be taken to control mosquitoes besides aerial spraying?

Eliminate any standing water (even tiny amounts) to prevent infected mosquitoes from laying their eggs (breeding) in standing water.

Use window and door screens to block infected mosquitoes from entering your home, workplace or children’s schools.

Use EPA-registered insect repellents to prevent getting bitten. EPA-registered means the product works and is safe when you follow the directions.

Dress in light-colored clothing, long pants, and long sleeves and try to avoid areas where mosquitoes are present.

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Bill to ban a toxic pesticide needs your support

H. R. 230 has been proposed for the US Congress to ban all use of the pesticide chlorpyrifos. Basically:

10 chlorpyrifos shall be deemed to generally
11 cause unreasonable adverse effects on the environ-
12 ment due in part to dietary risks to humans posed
13 by residues of that pesticide chemical on food;
14 the Administrator of the Environmental
15 Protection Agency shall cancel the registration of all
16 uses of chlorpyrifos…

Download the bill and see the latest info here.

Contact Chester County rep Chrissy Houlahan to ask her to support the bill here.

Although the EPA banned most residential uses of organophosphates like chlorpyrifos in 2001, it has so far been turned back in banning chlorpyrifos in agriculture and mosquito control.

Although Chester County has not been spraying chloripyrifos to try to kill adult mosquitoes, nothing currently prevents it from doing so.

More background here. Also search chlorpyrifos on our site for posts like here.

Blackberry Leaves Decompose to Thwart Mosquito Breeding

Beyond Pesticides, December 21, 2019)

A study at the University of Maine (UMaine) finds that adding blackberry leaf litter in stormwater catch basins creates an “ecological trap,” enticing mosquito females to lay eggs in sites unsuitable for larvae survival. Employing this new and incredibly viable “attract-and-kill’ tool for mosquito control shows potential for preventing the breeding of mosquitoes that may carry insect-borne diseases, especially in urban environments. Stormwater catch basins regularly accumulate leaf litter, which serve as habitat for the mosquito species Culex pipiens (Cx. Pipiens) that may carry West Nile virus.

Previous University of Maine research discovered decomposing leaf litter from Amur honeysuckle (Lonicera maackii) and common blackberry (Rubus allegheniensis) produces chemical compounds that attracts and stimulates Cx. Pipiens female to oviposit, or lay eggs.

Investigating the attractiveness and lethality of varying catch basin conditions to mosquitoes, researchers hypothesized that blackberry leaf litter could be shown to be lethal to developing mosquito larvae, and, therefore, act as a natural ecological trap for Cx. Pipiens….

read more at Beyond Pesticides

Who says storm drains are a big mosquito problem?

The PA Department of Environmental Protection, that’s who!

We usually call them “storm drains” but others use the term “catch basins” or “inlets.” In any case, that’s where runoff from streets goes through a grill and disappears from our sight. But then were does it go? It should drain by gravity though a pipe system and eventually flow into a stream. That’s a problem for the stream, because street runoff can be polluted, e.g, by car and animal wastes.

But when water is able to remain standing in the storm drain, it provides an ideal habitat for mosquitoes to breed! Then those storm drains need to be “treated” (with a larvicide like Bti) to keep larvae from maturing there into adult mosquitoes. Here’s what PA DEP says (you have to keep refreshing the URL in your browser to find this photo and commentary):

What is supposed to happen? Has it been happening?

Some questions derived from CDC mosquito control guidelines:

1. Where has the County engaged in source reduction, as recommended?

The only source reduction we know of has been undertaken by West Chester Borough to prevent water from standing in storm drains. Does anyone know of other examples?

2. Where has the County engaged in larval mosquito control, as recommended?

They have told us that they do so, but so far have said they do not have records for 2015-17 and do not have time to tell us where for 2018; our Right to Know request on this with the PA Department of Environmental Protection is pending.

3. Has the County maintained a database of aquatic habitats to identify the sources of vector mosquitoes and a record of larval control measures applied to each (last paragraph below)?

From point 2 above, it would seem doubtful; but the public has a right to know, and we will.

Source material: Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, “West Nile Virus in the United States: Guidelines for Surveillance, Prevention, and Control,” 2016, p. 33. (See the points we have put in boldface below. Download the full publication here).

Integrated Vector Management

Mosquito abatement programs successfully employ integrated pest management (IPM) principles to reduce mosquito abundance, providing important community services to protect quality of life and public health (Rose 2001). Prevention and control of WNV and other zoonotic arboviral diseases is accomplished most effectively through a comprehensive, integrated vector management (IVM) program applying the principles of IPM. IVM is based on an understanding of the underlying biology of the arbovirus transmission system, and utilizes regular monitoring of vector mosquito populations and WNV activity levels to determine if, when, and where interventions are needed to keep mosquito numbers below levels which produce risk of human disease, and to respond appropriately to reduce risk when it exceeds acceptable levels.

Operationally, IVM is anchored by a monitoring program providing data that describe:
• Conditions and habitats that produce vector mosquitoes.
• Abundance of those mosquitoes over the course of a season.
• WNV transmission activity levels expressed as WNV infection rate in mosquito vectors.
• Parameters that influence local mosquito populations and WNV transmission.

These data inform decisions about implementing mosquito control activities appropriate to the situation, such as:
Source reduction through habitat modification.
• Larval mosquito control using the appropriate methods for the habitat.

• Adult mosquito control using pesticides applied from trucks or aircraft when established thresholds have been exceeded.
Community education efforts related to WNV risk levels and intervention activities.

Monitoring also provides quality control for the program, allowing evaluation of:
• Effectiveness of larval control efforts.
• Effectiveness of adult control efforts.
• Causes of control failures (e.g., undetected larval sources, pesticide resistance, equipment failure)….

and p. 34:

Larval Mosquito Surveillance

“Larval surveillance involves identifying and sampling a wide range of aquatic habitats to identify the sources of vector mosquitoes, maintaining a database of these locations, and a record of larval control measures applied to each. This requires trained inspectors to identify larval production sites, collect larval specimens on a regular basis from known larval habitats, and to perform systematic surveillance for new sources. This information is used to determine where and when source reduction or larval control efforts should be implemented….

“Why don’t they just spray and kill all the mosquitoes?”

Yes, people may wonder: “Why don’t they just spray and kill all the mosquitoes?”

First, it’s impossible to kill all the mosquitoes. Any spraying, including from a truck as done by the County, kills only the portion of mosquitoes that happen to be flying around at the time and encounter toxic droplets. We have seen figures of up to an 80% kill rate (yes, this is a serious poison) but no really authoritative figure.

But suppose 20+% of adult mosquitoes survive (and any out of the spray zone, sheltered at the time in thick foliage, or in inaccessible areas like inside bulkheads or hollow trees, will not be affected). The females, at least, will be happily flying around the next day biting people and laying eggs as usual.

The hundreds of eggs that each female lays in stagnant water are affected by spray. Those eggs will become larvae, pupae, and adults, all within a week in hot weather like now.

And current larvae and pupae will not be affected by spray either.

And not all mosquitoes are created equal. Specifications require that spraying occur only in the evening, when honeybees are less active. Disaster for bees ensues if spraying occurs at other times.

Our home-grown mosquitoes, the ones that at least give us an auditory warning hum as they circle us looking for bare skin, tend to be active in the evening; however, the recently established “Asian Tiger” mosquitoes, the silent biters, tend to be active during the day and therefore are not much affected by spraying. Killing off some of the “regular” mosquitoes probably just opens the airways to more Asian Tigers.

Furthermore, anti-mosquito spray actually kills mosquito-eaters like dragonflies and toads, to say nothing of insects that we enjoy seeing or that are important to ecological balance like butterflies.

The County Health Department does not spray for the comfort of people who wish to be outside without the recommended bug repellents, long sleeves, and long pants. People outside need to weigh those nuisances against the nuisance of being bitten. The Health Department is not the Department of Outdoor Living.

Finally, proper public policy is to spray only, in the words of the Chesco Health Department, “after exhausting all other available mosquito control strategies.”

The prime non-toxic mosquito control strategy is larviciding suspect standing water. Individuals can larvicide on their own property but not on public property. We are glad to say that the Borough of West Chester is taking steps for two employees to receive the relatively simple licensing to do that, and we hope other municipalities will do the same.

Currently, the County does the larviciding but obviously needs to be informed where the problem areas are in such a large county. In West Chester, our Adopt A Drain program is clearing drain grills of plastics and other detritus and informing the Borough of drains that need cleaning below grill level or larvicing where they are holding standing water.

Example, as of Aug. 30, 2018: the storm drain at the NE corner of E. Nields and S. Matlack streets. If you check it out, you’ll see a water reflection at the bottom. After the dry last week in August, this drain could already have released swarms of adult mosquitoes to the neighborhood. In dry weather, mosquitoes could also be breeding in stagnant areas of Goose Creek and Plum Run, including water backing up in drainage pipes entering the stream. (Water samples are needed to check it out.)

If residents anywhere are aware of storm drains with standing water, they should inform their municipality. And of course, we should all patrol our own property, even for something as small as a bowl holding water under a potted plant, and put in a helpful word to neighbors who may not be addressing the issue. For some egregious “Case studies in what to avoid,” see here.

Carta de la Alcaldesa Dianne Herrin: ¡No me rocíes!

verano del 2018

Ahora que ha llegado el verano, podemos disfrutar todo lo que el aire libre tiene para ofrecernos, desde jardinería y largas caminatas por el pueblo hasta los asados al aire libre. Desafortunadamente, el clima más cálido también trae pestes no deseadas, incluyendo los mosquitos, que pueden difundir enfermedades como el Virus del Oeste del Nilo.

En 2015, la alcaldesa Carolyn Comitta creó la Fuerza de Tarea del Oeste del Nilo (West Nile Task Force), formado por líderes del municipio, empleados, un grupo de ciudadanos activos conocidos como, Don’t Spray Me! (¡No Me Rocíes!), y el Departamento de Salud del Contado de Chester (Chester County Health Department). El objetivo de la Fuerza de Tarea del Oeste del Nilo (WNTF) es ayudarnos a todos a tomar medidas sencillas y no tóxicas para controlar los mosquitos, para que el Departamento de Salud del Contado de Chester (CCHD) no encuentre una razón para rociar nuestro Municipio con insecticidas.

Las investigaciones científicas muestran que los insecticidas químicos son relativamente inefectivos porque no impactan a los huevos de los mosquitos, larvas o pupas. Además, los insecticidas son tóxicos para los depredadores naturales de los mosquitos, como las libélulas y las ranas, también como a las abejas, las mariposas, los gatos y las personas químicamente sensibles.

Gracias a los esfuerzos para eliminar el agua estancada (un criadero de mosquitos), nosotros hemos visto un gran éxito, sin rociarles, dirigido por el Departamento de Salud del Contado de Chester (CCHD) en el condado durante los últimos años. El Departamento de Obras Públicas trabaja continuamente para eliminar los problemas de agua estancada en las bocas de tormentas; y, con más de 100 capitanes del bloque, ¡No me rocíes! (Don’t Spray Me!) los ciudadanos vigilan los mosquitos y nos ayudan a todos a manejar los mosquitos de manera segura.

Por favor únase a nosotros para tomar algunas medidas sencillas para eliminar el agua estancada en su propiedad limpiando las alcantarillas del techo regularmente, manteniendo los contenedores de basura con tapas ajustadas, cambiando los baños de las aves, aplicando larvicidas al agua estancada, ¡y más! Para obtener información, visite el sitio web del municipio: http://www.west-chester.com/491/Mosquito-Awareness/.

¡Gracias por mantener el Municipio West Chester segura, saludable y ecológica para todos!

Les saluda amablemente,

Alcaldesa Dianne Herrin
Borough of West Chester
DHerrrin@west-chester.com

traducción por Megan James

Health Dept. wants to spray West Chester

And we don’t want them to. Stay tuned.

Download the Health Dept. announcement here: West Chester Spray 8-16-18

We keep having to point out that the phrase “to prevent West Nile Virus” in the press release title makes no sense. The West Nile virus is carried in birds, especially crows, and then is picked up by mosquitoes that bite the birds, and those same mosquitoes can then bite people. But the transmission chain to humans must be really weak, because this whole year PA has had only one possible identified human case, not definitely verified and not critical.

About this particular spray plan: Note from the maps below that the proposed spray area would include almost all of the S. half of the Borough and most of the NE (including Marshall Square Park, where the Borough fended off spraying 3 years ago).

The County Health Department’s press release says: “People who are concerned about exposure to mosquito control products can reduce their potential for exposure by staying indoors with children and pets when their neighborhood is being sprayed.” That is a very low-level warning. Of course, everyone ought to be concerned about any pesticide being directly sprayed on them or infiltrating their dwellings.

But how does that advice play out in an urban area like downtown West Chester? What will people here be doing on a Thursday eve, other than sitting at home with their children and pets?

Although spraying is not scheduled right on Market and Gay Streets, it would pass really close to them, and of course spray drifts. Are people enjoying their outside drink or dinner in the center of town going to have methoprene drifting onto them and their food and into their lungs? Is West Chester going to earn the reputation of a place to avoid patronizing?

If just one hypersensitive person dining outside or inadvertently walking through the spray area has a serious adverse reaction, or one small asthmatic child in tow has to be rushed to the ER, that is going to be big liability. For whom?

For the County, which does the spraying? (Let’s be clear: the County decides when to spray, not the State.) The restaurant owner who could be said to have the duty to close down outdoors for the evening? The Business Improvement District, unless it acts to get downtown closed off? The Borough, if it does not make the decision to close the parking garages and post warning signs? This is a real morass. It’s not like spraying a rural area where houses are 500 feet apart with long driveways.

How about West Chester University? The whole campus north of Rosedate is in the spray area. Are all the students going to be told to stay in their rooms from 8 p.m. till the next day? How about those coming back from an off-campus job or the Library?

The Health Department really has not thought this through. If they wanted to make a more reasonable case, they would be proposing to spray only in the immediate vicinity of what are apparently the 3 trap sites with high readings: College Ave at the pumping station, Green Field, and Magnolia St.

The Health Department releases its info selectively to make its own pro-spraying case. Where are the other 28 traps in the Borough? What are their readings? Why do they want to spray the NE but not the NW? It’s full of mysteries, and that’s the way they seem to want it. But we don’t. “Trust us” doesn’t work any more, and especially now that Chester County has become all too familiar with the PA DEP, which is the state resource on both pipelines and mosquitoes.

When Don’t Spray Me! filed a Right To Know request, the Health Department said it did not know where it larvicided in 2015-17; and they also say they don’t have time to tell us where they larvicided this year. They say they spray only “after exhausting all other available mosquito control strategies” and they don’t even know where they have larvicided, which is the most effective anti-mosquito treatment in known breeding sites like storm drains and stagnant bodies of water?

If the HD can’t do better to explain its actions and consider the effects on a complex urban population, it needs to be stopped until there is greater accountability in the interest of the public and the environment.

NE West Chester:

 

Southern half of West Chester:

Case studies in what to avoid


Above-ground pools are often forgotten or abandoned and are perfect hosts for organic matter and, consequently, mosquito families. (In-ground pools usually have enough chemicals to deter mosquito breeding, but beware of water accumulating on pool covers!)


Puddle dug by cars at the edge of the road. If it stays wet for 7 days, it will be productive!


Clogged eave about 7 feet off the ground, easily accessible to mosquitoes (they will fly much higher too). The obstruction at the far end (the low end, over the downpipe unless there is a construcvtion error) needs to be cleared regularly.


Looking down this grill over a storm drain, you can see sky reflected back to you from water standing at the bottom. A beacon to egg-laying mosquitoes!

Trash can lid with larvae
Overturned trash lids can hold water. Lids should be tightly affixed to containers at all times in order to keep out water and other common pests like rats.

 

 

Flat roof syndrome. For some reason architects or builders can’t always figure out drainage, or else the roof sags over time. Yes, mosquitoes fly pretty high. If the roof retains water for a week after eggs are laid, the roof is a breeding site!

Prevention of Mosquito Breeding at Sartomer’s West Chester Site

The Sartomer Company, which has a production facility at 610 S. Bolmar St., West Chester, Pennsylvania, informs us that:

“The Sartomer site in West Chester is diligent about controlling standing water that could potentially harbor mosquito larvae. Dikes containing storm water runoff at the site are drained daily to eliminate standing water. The site’s waste water treatment holding pond, which has standing water by design, is treated with biological agents to control the potential for mosquito breeding. These efforts are among many actions that the site takes in order maintain a safe workplace and to be a good member of the community.”

Don’t Spray Me! will welcome, and will gladly post, similar statements from other Chester County businesses.


Sartomer in its neighborhood, courtesy of Sartomer Co. (S. Bolmar St., at the bottom, E. Union St. at the right, Goose Creek at the back, then S. Adams and other streets).