This summer, several prairie cities faced an unprecedented surge in mosquito populations, leading to a shortage of bug spray in stores across Manitoba, Saskatchewan, and Alberta. Data from the City of Edmonton revealed a 15-fold increase in mosquitoes in July compared to the previous year, although not reaching record levels. Saskatoon and Winnipeg also reported higher mosquito numbers this July than in the previous year.
Experts attribute this mosquito boom to the record rainfall experienced in southern Ontario, creating ideal breeding conditions for the floodwater mosquito species Ochlerotatus trivittatus, known for laying eggs in water-filled areas. Fiona Hunter, a professor at Brock University, noted a significant rise in this mosquito species in southern Ontario due to the abundant rain this year.
The persistent biting nature of Ochlerotatus trivittatus has resulted in increased human-mosquito encounters, contributing to the perception of a severe mosquito season. The heavy rainfall in southern and southwestern Ontario triggered the hatching of dormant mosquito eggs, exacerbating the issue.
As temperatures cool down, mosquito populations are expected to decline. Mosquitoes struggle in extreme heat and perish in cold weather, with colder temperatures signaling their disappearance. Recent cold snaps in Alberta have already led to a decrease in mosquito numbers.
Although Edmonton and Calgary faced a challenging mosquito season earlier, the populations have dwindled due to recent colder weather. However, a warm fall has somewhat delayed the decline in mosquito numbers. As temperatures rise again in the region, mosquitoes may reappear, but not to the extent experienced in central Canada.
