Manitoba residents may want to keep the bug spray close this summer. After a notably wet June and localized flooding across parts of the province, entomologists say conditions are primed for a longer and more intense mosquito season.
Heavy rainfall has created widespread standing water, the perfect breeding ground for Aedes floodwater mosquitoes — the aggressive biters that emerge in huge numbers after major rain events. Experts note that when saturated soil and pooled water persist for weeks, multiple hatching cycles can occur, extending mosquito activity well into mid‑summer.
Flooding adds another layer of concern. When rivers spill into low‑lying areas, they leave behind shallow, warm pools as water recedes. These temporary wetlands are ideal nurseries for mosquito larvae, allowing populations to surge rapidly. With parts of Manitoba experiencing above‑average precipitation, the province is seeing exactly the kind of conditions that fuel explosive mosquito growth.
Trap Count Snapshot
(Week of June 17–23)
- Floodwater mosquitoes — 1,240 average per trap (↑ 180% from previous week)
- Culex tarsalis — 42 average per trap (↑ 60%), still below West Nile risk threshold
- Overall nuisance index — Moderate to High
- Primary drivers — standing water, saturated soil, warm overnight temperatures
Public health officials continue to monitor Culex tarsalis, the species capable of carrying West Nile virus. While these mosquitoes thrive in hot, dry periods later in the season, a wet start can still boost early‑season numbers by expanding available habitat.
If current weather patterns continue, experts say the province could be in for a mosquito season that lingers longer than most would like.
