By Claire Kremen, Professor of Environmental Science, Policy, and Management and Co-director of the Berkeley Food Institute.
Like the European Union – which on Dec. 1 boldly began a two-year ban on selected pesticides thought to be harmful to honeybees and other pollinators – the United States should help protect pollinators by banning these pesticides. But the United States should do far more, and become a world leader in championing sustainable alternatives to harmful pesticides.
Pollinators are vital to our food supply and to California’s agricultural economy. They provide over one third of the food that we eat, improve production for 75 percent of all crop species, and are essential for many key crops grown in California, such as almonds, avocados, apples and cherries. Pollinators’ contribution to Californian agriculture is estimated at $2.7-6.3 billion per year.
The pesticides just banned in Europe are all neonicotinoids, neuroactive insecticides similar to nicotine. Their known impacts on bees range from interference with foraging and navigation (which reduces their ability to pollinate crops) to death.
A California native bee species Bombus vosnesenskii, or yellow-faced bumble bee, forages on almond flowers. (Alexandra Maria-Klein photo)
A tide of scientific evidence is accumulating that implicates these compounds in Colony Collapse Disorder, a phenomenon that has decimated honeybee colonies in the United States since 2006. Additional studies show that so-called neonics have crippling effects on wild pollinators. A massive bumblebee kill occurred last summer in Oregon following application of neonics to several ornamental trees.
Some defend neonics, which primarily target insects, arguing that farmers may revert to even more broadly toxic pesticides if these compounds are banned. This fear may be valid, but it is not an adequate justification for continuing to use chemicals that may seriously disrupt pollinator health.
Instead, policy makers should strive to drastically reduce use of all pesticides (insecticides, fungicides, herbicides, etc.) that have been shown to be harmful to humans and the environment, so that the alternative to a questionable product like a neonic is not something worse! Specifically, U.S. policies should create appropriate incentives in the Farm Bill and other policies, and should designate research funds to identify and promote sustainable alternatives to synthetic pesticide use.
The continued widespread use of neonics could have important economic consequences. California could be greatly affected – the entire U.S. almond industry, which is completely dependent on pollinators for nut production and is worth $3 billion per year, is located here. Certainly the U.S. Environmental Protection Agency should ban the use of neonic pesticides indefinitely, unless they are proven in the future not to be detrimental to pollinator health.
But the burden of proof is not as simple as testing a single chemical in a lab. It’s a grave concern that breakdown products of some neonics – that is, new chemical compounds produced from metabolism of the original neonic chemical – can have even more toxic effects on insect pollinators than the marketed products.
Scientists have just begun to examine how neonics might be interacting with other pesticides to affect bee health. Little is yet known about how these compounds, or their breakdown products, might combine with other pesticides used simultaneously or sequentially on farm fields to affect bee or human health.
Also, targeted pesticides such as neonics are not necessarily free from impacts on mammalian, and therefore, human, health. Recently, imidacloprid, one of the most widely used neonics in our country and one of three now banned in Europe, was shown to cause skeletal abnormalities and to compromise the immune systems of developing rat fetuses, in a study published in the journal of Food and Chemical Toxicology. Chronic exposure in pregnant women could have similar trans-generational effects as those observed in this study.
Pesticide pounds: 1.5 billion
The U.S. EPA does, of course, have substantial regulatory procedures for evaluating pesticides before they are marketed, but these cannot possibly include testing all of the possible breakdown products and their potential synergistic reactions with other chemicals released into farm fields, or examining all of the potential trans-generational effects in humans or other organisms. Rather than attempt the impossible, it is far more sensible simply not to release toxic pesticides into our water, air, and soil in the first place.
As a case in point, on 37 farm fields in one county in California’s Central Valley, where we investigate how farm management practices affect native pollinators, each field in our study was sprayed, on average, 24 times, in 2012 (the range was 2 to 87 times!), collectively including 84 different active ingredients. This variety makes for a potent cocktail with truly unknown effects on pollinators and other organisms.
Each year 1.5 billion pounds of pesticides (the amount refers to the active ingredients) are released in the United States. The amount of pesticides used globally is similarly astounding (5 billion pounds per year of active ingredients). If current trends in pesticide use continue, these amounts are projected to increase 2.7 times by 2050.
Alternatives to synthetic pesticides do exist. It is a fallacy to presume that growers and scientists, working together, cannot devise high production practices that are largely or completely pesticide-free. Many studies and experiences in practice show the feasibility of alternative approaches. In East Africa, for example, clever agro-ecological research conducted over 15 years revealed that growing selected fodder, legume and grass species in combination with staple maize and sorghum crops permitted control of two serious pests that plague these crops. As of 2010, this system was adopted by over 30,000 small farmers and not only tripled yields, on average, but also improved livestock production, incomes, soil fertility, and, through these, positively impacted women’s empowerment.
In the United States, a long-term study in Idaho showed that using more complex rotations than the typical two-year corn-soy rotation can control weeds without resorting to herbicide use (some of which are known endocrine disruptors), while maintaining profitability. Interestingly, earlier research and experience showed that similar long-rotations and cultural methods for corn and soy also help farmers to weather severe droughts, such as the one experienced in 2012 in the US corn belt. These examples demonstrate that pesticide-free approaches used in sustainable agriculture are equally or more productive than pesticide-dependent approaches and often have other tangible benefits. They underscore also the role that research can play in developing effective alternatives.
Beyond prioritizing research on alternatives to pesticides and banning neonics unless proven to be safe, our government should provide far more funding through the Farm Bill or other policies for programs that support growers who adopt sustainable agricultural methods, like planting habitat for natural enemies of crop pests to reduce or eliminate usage of hazardous pesticides.
Instead, agricultural spending from the Farm Bill has primarily subsidized conventional corn and soy production and crop insurance programs, without requiring improved environmental practices. It’s time to stop reinforcing a toxic status quo. We need to pass a Farm Bill and strengthen other programs that can provide the incentives and information farmers need to adopt more sustainable practices.
Contributors’ biographies: Leithen M’Gonigle is a postdoctoral researcher working with Claire Kremen at UC Berkeley on how wild pollinators contribute to our food supply and what farming practices can promote them. Lori Ann Thrupp is a sustainable agriculture expert and the executive director of the Berkeley Food Institute, a new center dedicated to promoting a food system that is diverse, just, resilient and healthy.