This is a short reference for the chemicals used here.  It is your responsibility to read and follow all directions provided by the manufacturer.

Important:  if you have pets, read the labels carefully.  The concentrations used here are extremely small, but caution is advised.

Important: if you share chemicals with neighbors, please LABEL the containers and include a description of how it should be used (0.5 ounces per gallon, or 1 tsp per 100 square feet, etc).  Boric acid looks a lot like Ant Dust, and your neighbors could easily get them mixed up.

Boric Acid

See the Fact Sheet.  Used for the water bath.

Boric acid has been shown [Bhami and Das, 2015] to be most effective at a dosage rate of 1 gram per 100 ml of water.  This works out to be about one generous ounce per gallon (40g per 4000ml).  More than this was found to slightly repel the females, less was found to have a kill rate of less than 100% for the larvae.

An advantage of boric acid is that it is long lived. I am running a test with one trap, currently at 6 weeks, where 100% of healthy larvae added to the solution die within 24 hours when placed in the water bath. (Pupae are not affected because they are no longer feeding).

Update: after 12 weeks, most of the larvae die, but the larger (older) ones appear to survive.  So three months is probably the maximum time boric acid might be effective.


A man-made pyrethrin used for the landing strip.  See the Fact Sheet.

It is considered to be very safe.  Humans eating several grams of deltamethrin (about 10 pounds of the Ant Dust) recovered completely within 48 hours. [H Rehman, et al. 2014].  The toxicity for fish is considered high.  It does not appear to affect worms.

Deltamethrin is available as a powder (Terro Ant Dust, or Defense Dust, both 0.05%).  It is also available in liquid form (Defense SC) but it is more concentrated. The total amount used on the landing strip is about 0.1 mg.


See the fact sheet.  Used for the landing strip.

Bifenthrin is a man-made pyrethroid similar to the pyrethrins made by Chrysanthemum plants.  It has low repellent action against mosquitoes compared with other insecticides, including deltamethrin (Ant Dust). Bifenthrin is considerably more stable than deltamethrin. Because of this, bifenthrin is banned in some states such as NY because of the fear that it will accumulate in the ecosystem.  It is permitted in Hawaii, and most other states. Note that it is approved for use in food preparation and handling areas.

Researchers [Williams CR et al, 2007] have shown that under field conditions, landing pads treated with bifenthrin retain 100% of their effectiveness after 4 weeks.  No research has studied longer exposures, but it is likely that it will remain effective considerably longer.  Here, we will assume it will last at least as long as the Spinosad. Sunlight (UV) destroys it so it must be kept in the shade.

Bifenthrin treated landing strips must be dried before use. Once dry, they may be stored indefinitely in a dark, dry location before use. Several groups are making hundreds of these to share with people wanting to make the Four Month Trap. Contact for more information.


See the Fact Sheet.  Used for the water bath.

S-methoprene acts like an insect hormone and prevents larvae from metamorphosing into adults.  It is the active ingredient in Tango, commonly used on the Big Island to fight Little Fire Ants.

It has very low toxicity to animals, but can be toxic to some fish, and highly toxic to freshwater invertebrates (which is why we use it in the water bath).

In many countries, s-methoprene is used to treat drinking water for humans during disease outbreaks.  This use has not been approved in the US.


See the Fact Sheet. Used for the water bath.

Used for the water bath.  Numerous research papers show the efficacy of spinosad (typically with a 10 ppm concentration) lasts for greater than 20 weeks under field conditions provided the trap is not in the sun. [Bond JG et al, 2004].

Spinosad is also approved by the USDA for use in Organic farming.


See the Fact Sheet.  Used for the water bath.

Bacillus Thuringiensis is considered by many to be an organic treatment, and is used extensively in agriculture.  It must be refreshed regularly.

It has very low toxicity.  The strain used in Mosquito Bits, and Dunks is “israelensis” is not toxic to honeybees.




If you cannot get the exact chemicals described here, then you must carefully compare the ingredients. Often concentrations will be different, so you will need to make calculations to determine how much you should use.  Contact for help with this.