Threats to Monarchs from Pesticides
What are Neonics and Why is their Use Banned for Residential Gardens in Marin?
Neonicotinoids have been banned in the European Union since 2018. While the US federal government has not restricted their sale, a number of states have moved independently to do so for residential, non-agricultural purposes, including California, Colorado, Nevada, Maryland, Connecticut, Maine, Vermont, Massachusetts, New Jersey, Minnesota, Washington, New York, and Rhode Island. They continue to be used extensively in other states.
Some states also restrict agricultural use, such as Vermont, which banned neonicotinoid-treated seeds for certain crops.
California banned over-the-counter sales of lawn and garden neonicotinoid pesticides on January 1, 2025, but their use is still permitted on land used for agriculture by licensed pesticide applicators.
Another persistent risk to monarchs comes from neonicotinoids, or neonics, a class of insecticides widely used in agriculture and landscaping. Monarchs near agricultural land are often exposed to neonics when crops are sprayed with this substance. While initially marketed as less harmful than other insecticides, neonics are now known for their devastating impacts on pollinators and beneficial insects. Research on bees reveals that neonics affect the brain and reproductive system, deplete their energy, and prevent them from expelling parasites.
