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fungicides

October 24, 2024

Agricultural chemicals are more toxic to insects than previously thought

By Douglas Main

New research provides evidence that chemicals used in farming may be more harmful to insects than previously thought, contributing to worldwide declines in important species.

In a wide-ranging, first-of-a-kind study published October 24 in the journal Science, scientists found that extremely small, sublethal concentrations of over 580 insecticides, herbicides, fungicides and other chemicals can have serious negative impacts on the behavior and subsequent survival of certain insects. The scientists tested some of the chemicals on fruit fly larvae, mosquitoes, and butterflies.

The results were “very shocking,” said study co-author Justin Crocker, a researcher with the European Molecular Biology Laboratory in Heidelberg, Germany.

The study bolsters the case that agrochemicals play a big role in plummeting populations of insects, a phenomenon that can gravely harm food production since certain insects are needed to pollinate key food crops.

In the paper, researchers exposed 75 fruit fly larvae to three concentrations of 1,024 different agrochemicals. The smallest level tested (2 micromoles) is well within the range found in the real world; for example, it’s not uncommon to find this concentration of the herbicide glyphosate in streams near crop fields.

After only 16 hours of exposure, they transferred the insects to vials containing chemical-free food, and filmed their behavior. More than half of these substances caused discernible changes in the behavior of developing insects.

March 13, 2023

Scientists warn pesticide impacts may be worse than we thought

In California, regulators have rolled out a plan to eliminate “high-risk” pesticides from agricultural and urban use. In Mexico, officials have announced a ban on the widely used weedkiller glyphosate. And in Canada, regulators have implemented some new pesticide restrictions and are reviewing the potential for others.

The moves, which are also playing out in various forms around the United States, have drawn opposition from chemical and farm industry forces. But supporters say they don’t go far enough to adequately protect human and environmental health.

Three University of British Columbia researchers recently published a paper that summarizes what they say is a growing body of evidence showing that pesticides are having harmful ecological impacts beyond what is already well understood, and that these impacts are not being recognized by current testing and regulations. The authors of the paper looked at dozens of studies to draw their conclusions.

The New Lede had a conversation with lead author Risa Sargent about the team’s findings. Sargent is an associate professor of applied biology within the Faculty of Land and Food Systems at the University of British Columbia. She and colleagues reviewed studies from around the world, finding alarming results.