American companies began a large‑scale release of mosquitoes in the Montreal area on Friday evening, August 7, 2026. The operation involved dropping hundreds of thousands of insects into the environment with the explicit aim of suppressing the invasive tiger mosquito, a known carrier of dengue, chikungunya and Zika viruses.
The method being tested relies on a biological control strategy. By flooding the area with large numbers of sterile or otherwise modified mosquitoes, the companies hope to outcompete the wild tiger mosquito population and reduce its numbers over time. The releases are coordinated to cover multiple neighbourhoods in the city, and the timing was set for late evening hours to coincide with the insects’ natural activity patterns.
Étienne Normandin of the Institut de recherche en biologie végétale de l'Université de Montréal is monitoring the project. His team is tasked with tracking mosquito density and assessing any changes in the prevalence of the disease‑bearing species. The institute’s involvement provides scientific oversight and data collection to evaluate the effectiveness of the mass‑release approach.
The initiative reflects a broader effort to address the public‑health threat posed by the tiger mosquito, which has become established in Quebec in recent years. By targeting the vector directly, the program seeks to lower the risk of mosquito‑borne illnesses in the local population. The test in Montreal is part of a series of trials by U.S. firms exploring biological control as an alternative to chemical insecticides.
If successful, the release could inform future strategies for managing invasive mosquito species across North America, offering a potentially sustainable tool for disease prevention without relying on widespread pesticide use.