Canada to grant continued registration for malathion

After a thorough re-evaluation of the insecticide malathion, the Canadian Pest Management Regulatory Agency (PMRA) has proposed to grant continued registration of products containing malathion for sale and use in Canada. However, some uses of malathion are required for phase-out because they are not supported by the technical registrant Cheminova Canada Inc. It voluntarily discontinued a number of residential uses including structural (pet quarters, indoor uses); companion animals (pet treatment); turf (broadcast turf/lawn treatment); and residential outdoors (broadcast/turf lawn treatment). The changes to the related product labels have been completed.

Malathion is a non-systemic insecticide and acaricide with contact, stomach, and respiratory action. Malathion is suited for control of a wide variety of chewing insects. Chewing insects, in general, are non-selective in their feeding behaviours as they typically ingest macerated whole leaf tissue. Insecticides with stomach-poison activity are more effective in controlling insects with chewing mouthparts such as beetles, grasshoppers and moth larvae. And being a MoA group 1B insecticide, malathion also plays an important role in delaying resistance when used in rotation with insecticidal active ingredients from different MoA groups.

Dietary, residential and occupational risks from malathion are not of concern by PMRA. However, additional risk-reduction measures are required on malathion labels. And additional risk reduction measures need to be observed in view of malathion poses a potential risk to terrestrial and aquatic organisms. Birds are at risk in and around the site of application due to the consumption of contaminated food items, and the risk cannot be mitigated. In order to minimize the potential exposure to aquatic organisms, strips of land between the agricultural field and the aquatic areas (buffer zones) will be left unsprayed. The width of these buffer zones will be specified on the product label.