West Nile revisited

West Nile virus prevention and control plans call for action from the landscape industry, in particular, pesticide technicians. Continued from last year’s efforts, control strategies will include standing water and catch basin larval control for mosquitoes, the common vector of the virus.

Bacillus thuringiensis israelensis (Bti) is the preferred insecticide of choice for standing water larval control. Sold as Vectobac, this biological insecticide has a low residual quality. Bti can be applied weekly, and is available to homeowners.

For storm water catch basins, applicators use Methoprene, a longer-lasting synthetic insect growth hormone that prevents the development of the insect from pupa to adult. Methoprene lasts up to three weeks. Several applications will be required over the mosquito breeding season.

The MOE continues to monitor for residual effects of methoprene, and has added the insecticide to the list of chemicals to look for when testing drinking water.

Applicators must obtain permission from the Ministry of Environment, monitor the area before and after treatment and post public notices prior to treatment. Applicators must also possess an aquatic exterminator’s licence. A total of 497 Mosquito and Biting Insect Licences were granted in 2003.

Last year, out of one million properties that received permits for WNV treatment, 639,669 properties were treated with Methoprene; 605 ha were treated with Bti out of the originally proposed 1962 ha.

Contact your municipality for complete details or visit Health Canada at www.hc-sc.gc.ca/pmrala/english/mosquito/mosquito-e.html. Posted to the web 2004-05-26.

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