
A little brown bat with white-nose syndrome. Credit: Marvin Moriarty/USFWS
Bats are often misunderstood and underrated creatures in nature. While some may fear them due to their portrayal in popular media, bats play a crucial role in pest control. According to the US Forest Service, bats can catch 1,000 mosquito-sized insects in an hour, making them valuable allies for farmers.
However, the spread of ‘white nose syndrome’, a fungus affecting bats in the US, has led to a decline in bat populations. This decline has forced farmers to increase their use of insecticides for pest control, potentially causing adverse effects on human health and infant mortality rates.
Research has shown that areas where bat populations have been decimated by white nose syndrome experienced a 31% rise in insecticide use and an 8% increase in infant mortality not due to accidents or homicides. This correlation highlights the important role bats play in maintaining ecological balance and pest control.

Tricolored bat from Avery County, North Carolina, with white-nose syndrome. Credit:Gabrielle Graeter/NCWR.
White-nose syndrome (WNS), caused by a fungus known as Pseudogymnoascus destructans or Pd, is a disease that affects hibernating bats. The fungus appears as a white fuzz on the bats’ faces, thriving in cold, dark, and damp environments.

White nose syndrome in bats. Little Brown Bat; close up of nose with fungus, New York, Oct. 2008. Credit: Ryan von Linden/New York Department of Environmental Conservation
During hibernation, the fungus attacks the bare skin of bats, causing them to become more active than usual and deplete their fat reserves needed for survival through the winter. Bats affected by white-nose syndrome exhibit unusual behavior, such as flying during the daytime in winter.
The Origins of White-nose Syndrome
White-nose syndrome was first observed in bats near Albany, New York in 2007, with reports and evidence dating back to 2006. The disease has since spread, resulting in mass fatalities among various bat species.
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White-nose syndrome has claimed millions of bats across North America, with some sites experiencing mortality rates as high as 90 to 100 percent. Efforts are underway globally to study the disease, its transmission, and potential control measures such as vaccines and habitat preservation to save bat populations from this devastating affliction.