Dursban 2.5G is one of the primary insecticides used by the City of Edmonton to control mosquito larvae in the aquatic stage.
Dursban 2.5 G is just one of about 30 different pesticides registered with Health Canada’s Pest Management Regulatory Agency (PMRA) with the active ingredient chlorpyrifos.
Use of chlorpyrifos as a pesticide has not now nor has it ever been banned by the Federal government, or any Province in Canada.
In the last decade, the manufacturer of Dursban 2.5G voluntarily removed all of their chlorpyrifos products that had a domestic label, or were used indoors in human residences.
There are still domestic products available in Canada through other manufacturers that use chlorpyrifos.
Of the various chlorpyrifos products in use for pest control, the use by municipalities for mosquito control accounts for less than 0.1% of the total chlorpyrifos use in the province. Most use of chlorpyrifos is in agriculture (Lorsban) for control of lygus bugs, armyworm, cutworms and grasshoppers, especially in canola production.
Every pesticide label in Canada is only registered for a five-year period, and must be renewed by the PMRA. The label for Dursban 2.5G was set to expire in 2014, and since Dow was no longer manufacturing the product (due to a limited market), it was expected that the label would not be renewed. However, the label was extended to 2019, allowing for continued legal use of the product until at least that time.
One of the largest municipal mosquito programs in Canada no longer uses Dursban 2.5G as part of their mosquito control program, however they do continue to use Malathion aerosols to control adults in residential areas, and use Dursban Turf (a chlorpyrifos product) as a spray on tree trunks in residential areas to control elm bark beetles. Neither of these techniques are used in Edmonton.
Dursban 2.5G is the only effective product available for use against mosquito larvae in the cold temperatures during the spring melt when the first generation of mosquitoes are developing. There are currently no viable alternatives for this use available in Canada.
Chlorpyrifos is a toxic substance, as are pretty much all pesticides, and as such must be used with care. The City’s use of Dursban 2.5G by professional applicators licensed by the Province, and according to the guidelines required by the Federal government is intended to minimize risk to human health, the environment and other organisms.
Only used on temporary and semi-permanent ponds (reduces exposure of non-target organisms; avoids affecting predators such as dragonfly larvae & fish; reduces chance of run-off into other aquatic environments; minimizes human exposure).
Used at the lowest rate of application possible for effective control and equipment calibration (reduces quantity of product used).
Granular product minimizes risk of application drift or post-application volatilization of chlorpyrifos, ensuring that product stays where it was applied.
Product is not used within 30m of an occupied building (reducing risk of human exposure).