Mosquitos

The facts about pelletizing our wetlands with Abate5 (Temephos) here in Bordentown Township:

 E X T O X N E T

Extension Toxicology Network/Pesticide Information Profiles

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho, and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University.

• Effects on aquatic organisms: Temephos shows a wide range of toxicity to aquatic organisms, depending on the formulation. Generally, the technical grade compound (tech) is moderately toxic and the emulsifiable concentrate (ec) and wettable powder (wp) formulations are highly to very highly toxic. The most sensitive species of fish is the rainbow trout with a temephos LD50 ranging from 0.16 mg/L (ec) to 3.49 mg/L (tech) [16]. Other 96-hour LD50 values are reported as: coho salmon 0.35 mg/L (ec), largemouth bass 1.44 mg/L (ec), channel catfish 3.23 mg/L (ec) to >10 mg/L (tech), bluegill sunfish 1.14 mg/L (ec) to 21.8 mg/L (tech), and Atlantic salmon 6.7 mg/L (ec) to 21 mg/L (tech) [6,8,13,16]. Freshwater aquatic invertebrates such as amphipods are very highly susceptible to temephos, as are some marine invertebrates such as mysids. The 96-hour LD50 of temephos in Gammarus lacustris is 0.08 mg/kg, and in stoneflies is 0.01 to 0.03 mg/kg [6,8,16]. Because the compound is an insecticide and is used effectively to control the aquatic larval stages of mosquitoes, black flies, and midges, its high toxicity to these organisms is not surprising. The product Abate 4E (46% emulsifiable concentrate) is very highly toxic to saltwater species such as the pink shrimp (LC50=0.005 mg/L) and the Eastern oyster (LC50=0.019 mg/L) [8]. The compound is nearly nontoxic to the bull frog with an LD50 of greater than 2000 mg/kg [8]. Temephos has the potential to accumulate in aquatic organisms. The bluegill sunfish accumulated 2300 times the concentration present in the water.

• Effects on other organisms: The compound is highly toxic to bees, with a direct contact LC50 of 1.55 ug/bee [13].

The clear choice is to allow the natural predators in our wetlands and watershed control the mosquito population. Killing the natural predators only forces us to use stronger and more lethal chemicals year after year.

• The increased ability to survive pesticide exposure is called resistance. Development of resistance to a pesticide can produce resistance to other pesticides with a similar active ingredient or that work in a similar manner. The ability to survive exposure to a chemical is often passed on genetically and will spread through a population.
• Pesticide resistance to older pesticides including organophosphates has been documented in many mosquito populations. (Temephos is an organophosphate).

The county has been spraying pelletized Temephos in our wetlands since the 1970’s to control the mosquito population. It has been found that after several years the vector population builds up resistance to the chemical temephos. Columbia, Brazil, Thailand, India, Cuba and many other countries are now wrestling with the problem of Temephos resistance. Instead of giving the residents a false sense of security, we have chosen to stop using Temephos until the county switches to a different control. It is our understanding that BTi will be used in 2015 for vector control.

Although we have sprayed in our watershed and wetlands for many years, it has not eliminated West Nile virus from our community. We have requested and the county has agreed to spray BTi, which has been found to be very effective and less toxic, in all areas of our Township where the vector population is problematic or West Nile is detected. 

For further information about how you can control mosquitos in your yard, or questions about vector control in our community you can click the link or call 609-298-2800 (Bordentown Township) or 609-265-5064 (Burlington County Division of Mosquito Control).

email: [email protected]