Waterloo: Researchers at the University of Waterloo may have discovered a new, pesticide-free way to limit mosquito populations in some area and reduce the spread of the West Nile virus. The study by Waterloo researcher Brad Fedy discovered that introducing hungry minnows into bodies of water where mosquitoes breed results in the minnows feeding on mosquito larvae, which dramatically decreases the number of adult mosquitoes capable of carrying the disease.
“The best strategies to limit mosquitoes start at the larval stage.
Unfortunately, in North America, control efforts are largely limited to
larvicides, which require a repeated application and have potentially
negative ecological impacts,” says Fedy. “Addressing the problem with
minnows provides many benefits in that it is low-maintenance,
cost-effective, better for the environment in many cases, and our
The study took place over three years and introduced minnows into ten
treatment reservoirs. Researchers monitored an additional six
Treatment ponds demonstrated suppressed levels of mosquito larva over
each season compared to controls with a model-predicted 114 per cent
decrease in larva density within treatment ponds.
“There are many potential advantages to using indigenous fish species
as an alternative for larval control including lowered environmental
impact, decreased costs regarding time and financial inputs, and the
potential for the establishment of self-sustaining fish populations,”
said Fedy. “This isn’t a complete solution to the dangers of West Nile,
but it should be considered as part of any plan to protect the health of
Fedy and his team discovered the method while researching sage grouse
populations in the intermountain west. Sage grouse populations suffer
adverse impacts from mosquitoes transferring viruses like West Nile and
investigated ways to mitigate those negative impacts. What they
discovered could also improve human health.