Imidacloprid is the world’s most popular pesticide, and highly controversial. It belongs to a family of neurotoxins, neonicotinoids, that is increasingly being blamed for colony collapse disorder—the sharp die-off of honeybees that has plagued North America since 2006.
The U.S. Fish and Wildlife Service, the National Marine Fisheries Service, the National Audubon Society, and the Xerces Society, which advocates for invertebrates, have all opposed the chemical’s use on Willapa Bay. But their protests are now moot. On April 16, the Washington Department of Ecology approved the spraying of imidacloprid on 1,500 acres of Willapa Bay and 500 acres of nearby Grays Harbor in order to kill the native shrimp that are wreaking havoc on the cash crop which happens to be non-native oysters.
Imidacloprid dissolves in water, meaning that fish will swim through trace quantities of the chemical and oysters will grow in an imidacloprid-laced bay. It will be a first: Imidacloprid has never been applied on water before in the U.S. Since the pesticide was designed for use on land, there’s little information on how it might affect anything marine from zooplankton to the green sturgeon to birds.
The label of a Bayer-made version of the pesticide, Merit, makes this explicit:
“This product is highly toxic to aquatic invertebrates. Do not apply directly to water, or to areas where surface water is present or to intertidal areas below the mean high water mark.”