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Welcome to Cass County, North Dakota
Larval Control Products
Measuring Product to be Applied to Water

This product list is designed to give you an understanding of what employees of Cass County Vector Control use as control materials for larval mosquitoes. This list also contains information to aid you with any questions you may encounter throughout the mosquito season. For information on products to purchase for home use click here.

Bti granules: Bacillus thuringiensis subspecies israelensis, commonly called Bti, is a microorganism that produces chemicals toxic to insects only when ingested by insects with an alkineline digestive tract. This is a common larviciding agent for control of mosquito. This agent is only effective toward the larvae stage of the mosquito. Bti microbes occur naturally in the environment and were registered in the United States for use as a pesticide in 1961 and reregistered in 1998.

Cass County applicators use Bti to treat large ponds and areas of standing water near pastures, homes, food crops, road ditches, and forestry areas for mosquito larvae. Bti granules are applied at a rate of 10 pounds per acre with a residual effect not exceeding 7 days. BTI easily breaks down in sunlight. This product is readily available to the public at most lawn and garden centers. Bti granules have the signal word "Caution" and displays very low mammalian toxicity.

According the EPA, "...microbial pesticides have undergone extensive testing prior to registration. They are essentially nontoxic to humans, so there are no concerns for human health effects with Bti or B. sphaericus when they are used according to label directions." The US EPA considers Bt's to be practically nontoxic to fish and birds.  Infact, under certain use patterns, Bacillus thuringiensis use is considered "organic" by the Organic Materials Review Institute (OMRI)  which determines the products that can be used on USDA approved organic farms. Additionally, even groups that are opposed to other pesticides recommend the use of Bti to control mosquitoes.

Bti is the most common pesticide used by Cass County Vector Control as well as a majority of mosquito control agencies throughout the US. Sample Label MSDS Fact Sheet

To learn about how Bti kills mosquitoes click here.

Vectolex CG:  The active ingerdient in Vectolex is Bacillus sphaericus, also a bacteria, and has a very similar mode of action as Bti. Field Aides encounter many drainage systems, storm drains, ditches and collecting pools in Cass County that hold water for extended periods of time. Vectolex is administered by hand at a rate of 5- 20 lbs. per acre, depending on the size of the site, soil type, and specimen collected. Vectolex has a residual up to 28 days if weather permits or no run-off intrudes the site treated.  Label MSDS

Altosid Pellets: Altosid pellets are applied to sites that require frequent treatments. Altosid pellets are insect growth regulators that are applied to areas of standing water with larval populations. The active ingredient is in mixed with carbon(charcoal) to form a dark, cylindrical pellet, and is dispersed by hand or backpack at a rate of 2.5 lbs of pellets per every acre of water. Under normal conditions a pellet should last for 30 days, however, if there is any flooding or run-off an application can be done more frequently. This product is used as a pretreatment before a rain event, and is applied to known breeding areas every 30 days.  Label MSDS

Altosid Briquettes: Altosid Briquettes are placed in sites subject to heavy flow of water. This insect growth regulator is in the form of a dark, cylindrical briquette that is dispersed by hand at a rate of 1 briquette per every 75 gallons of water or 100 sq.ft of area. Under normal conditions a briquette should last for 30 days. The lasting effect and size of this product makes it ideal for ornamental ponds and permanent water. A form of this product, Pre-Strike, is available to the public. Label MSDS

Altosid XR 150 day Briquettes: Altosid XR Briquettes are released into sites subject to heavy flow of water and are difficult to access on foot. This product contains an insect growth regulator that is used to control larvae populations.The product is in the form of a dark, cylindrical briquette that is dispersed by hand in shallow water (<2 ft. in depth) at a rate of 1 briquette per 100 sq. feet. Under normal conditions a briquette lasts for 150 days. Areas with alternate wetting and drying should not reduce effectiveness. The residual of this product allows Cass County employees to treat some breeding sites only once per season. Label MSDS

Agnique MMF and G: These products are monomolecular surface films intended to control larvae and pupae populations in standing water. When dispersed on the surface of water, the oil expands and covers the entire surface area. This prevents larvae and pupae from suspending at the surface to breathe. Agnique MMF is composed of a chemical called Poly (oxy-1,2-ethanediyl), alpha-isooctadecyl-hydroxyl, and it is applied by spraying the liquid through hand-held spray bottles. Agnique G is a granular form that was added to the program in 2008. The treatment rate that we use is roughly 0.2-0.5 gallons of Agnique MMF per acre of water. This is the only treatment for mosquitoes that have reached the pupal stage. Label  MSDS