After Hurricane Florence resulted in severe flooding across North Carolina in September 2018, many affected communities experienced a significant rise in mosquito populations, particularly larger and more aggressive floodwater mosquitoes. These mosquitoes hatched from eggs that had previously remained dormant in the soil, some for up to two years, until the heavy rains triggered their emergence.
Despite the notoriety of this mosquito outbreak, floodwater mosquitoes are frequently a nuisance in low-lying regions of the state. This summer, Tropical Storm Debby also led to an increase in mosquitoes in Brunswick and New Hanover counties. Forecasters now warn that Hurricane Helene may produce similar results. With predictions of heavy rainfall in central and western North Carolina on Friday, conditions are ripe for another surge in mosquito populations.
Michael Reiskind, an associate professor of entomology at North Carolina State University, holds extensive knowledge regarding these pests. He studied mosquito-borne viruses in his graduate research and has published multiple articles on mosquito biology. Reiskind explains that while floodwater mosquitoes do not pose a major health risk to humans, their large numbers can make outdoor activities unpleasant, particularly for residents in rural locations.
In an interview, Reiskind elaborated on various aspects of floodwater mosquitoes, including their rapid egg development. These mosquitoes are characterized by their ability to develop quickly after flooding, with some species maturing within just four to five days in warm conditions.
Although floodwater mosquitoes are not typically associated with human diseases, they can transmit heartworm disease to dogs, highlighting the importance of preventative measures that pet owners can take.
Reiskind noted that areas with low geographic relief, particularly the coastal plain, are more susceptible to mosquito outbreaks after significant rainfall. After a major rain event, mosquito populations can swell across parts of North Carolina, not just during hurricanes.
He also touched on the unpredictability of mosquito emergence from flooding, the potential efficacy of aerial insecticide spraying, and the challenges rural areas face in managing mosquito populations. Climate change is contributing to more intense rainfall events, which may lead to an increase in mosquito outbreaks in the future.
Reiskind concluded that while new technologies are being explored for mosquito management, such as genetic methods and targeted aerial applications, the practical application of these solutions remains challenging. Consequently, floodwater mosquitoes are likely to remain a persistent issue in the years ahead.