It’s time to strengthen pesticide regulation in Maryland

Efforts to better regulate pesticides are likely to come up in The General Assembly once again this year.

The 2020 session of the Maryland General Assembly will likely continue the recent trend of bills seeking to ban certain pesticides.

In 2016, Maryland was the first state in the nation to ban use by consumers of neonicotinoid insecticides. In 2018 and 2019, the legislature narrowly failed to pass bills to ban chlorpyrifos, an organophosphate insecticide associated with neurological problems in children. Some version of these bills is expected to return for consideration in 2020, along with a proposal to ban glyphosate, the active ingredient in the herbicide RoundUp.


There is little doubt that pesticides, together with habitat loss and increasing disease pressure, have contributed to significant degradation of Maryland’s ecosystems. Dramatic reductions in the number of insects and birds mean fewer pollinators and other ecosystem services, more invasive pests and less diversity and beauty in the landscape. It is also true that many pesticides are detrimental to human health, especially among children, who may be especially vulnerable. A recent study in the British Medical Journal found modest increases in neurodegenerative and behavioral disorders following perinatal exposure to many different pesticides, including chlorpyrifos and its common pyrethroid alternatives.

While banning chlorpyrifos might be appropriate, this step is unlikely to make us safer. Since 2003, use has declined, by as much as 95% on corn, while use of pyrethroids has become more common. As a result, dangerous pesticides continue to drift into populated areas, farm workers are still exposed and residues remain on food. An alternative regulatory approach, perhaps one modeled after pharmaceutical regulation, could be a more effective step to improve safety. There are several actions Maryland might take to create such a system.


First, the state could take a more proactive approach to pesticide registration and monitoring. While the Environmental Protection Agency will continue to oversee registration, distribution, sales and use of pesticides throughout the country, their relative risks and benefits in our state may vary from those in other states. This is especially true regarding use in environmentally sensitive areas. California and New York have recently used this regulatory authority to phase out chlorpyrifos use. This process has the advantage of allowing use in extreme situations when there are no reasonable alternatives. It also recognizes that lawmakers lack the time and expertise to thoroughly evaluate the scientific studies that often perplex experts, even those on Environmental Protection Agency Advisory Committees.

Second, the state might modify classification of pesticides beyond the current over-the-counter (available to the general public) and restricted-use (available only to certified applicators) categories. In a revised scheme, pesticides in the over-the-counter category should be reserved for those that have demonstrated safety over time. Within the restricted-use category, pesticides might be further subclassified according to their potential harm, with some classes requiring a specific license and additional reporting requirements, as is the case with controlled pharmaceutical substances.

Third, the state could increase its use of limits on pesticide use in order to minimize or eliminate specific harms. For example, the state might limit use of some pesticides to certain seasons or locations, expand buffer zones around schools and other public areas and require certain delivery methods and protective equipment.

Fourth, a pest surveillance system and access to manufacturer data might allow applicators to make better decisions regarding the most appropriate pesticide to use in a specific situation, thus reducing the need for broad spectrum chemicals that may have considerable “off-target” toxicity.

Fifth, all pesticide applicators — farmers, landscapers, and homeowners — should have access to appropriate education and training regarding pesticide use. Educational requirements could be enhanced for applicators who wish to use restricted-use pesticides, particularly those with private applicator licenses, which currently require as little as two hours of education and passing a certification test. Enhanced education and reporting requirements could also be extended to specific pesticides in order to prevent identifiable harms. For example, the EPA in 2018 required additional training requirements in order to use some formulations of Dicamba, an herbicide that has been associated with considerable drift.

In addition to new regulation that promotes smarter use of pesticides, we should all work to create diverse landscapes that research demonstrates are associated with fewer weed, microbial, and insect pests, and thus less need for pesticides. Visionary designer Buckminster Fuller once said, “You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete.” A new pesticide regulatory model could be a significant step in making our communities healthier and safer.

Tom Croghan ( is a physician and owner and winemaker at The Vineyards at Dodon in Davidsonville.