by Champions of organic farming have long demonstrated that it is friendlier to humans and the earth. But a new study in a California county found a surprising effect as their acreage grew: nearby conventional farms applied more pesticides, which likely kept their crops under increased insect threat, the researchers said.
Ashley Larsen, lead author of the study in this week’s Science magazine, said understanding what’s happening could be important in keeping organic and conventional farmers from harming each other’s operations.
“We are expecting an increase in the organism in the future. How do we make sure this isn’t causing unintended harm?” asked Larsen, an associate professor at the University of California, Santa Barbara.
In contrast, the researchers found that when organic farms were surrounded by other organic fields, their use of pesticides dropped, which the team thinks may be due in part to their reliance on bugs that are their natural enemies. for agricultural pests. Organic farms are allowed to use certain approved pesticides, but they often go to “good bugs” that prey on pests. “It seems that spatial clustering or focusing on organic areas could lead to that benefit or solution,” Larsen said.
The researchers analyzed 14,000 fields in California’s Kern County over a seven-year period.
Organic farm acreage has been increasing since 2000, although it still accounts for less than 1% of all farmland, according to the USDA. As that change occurs, Larsen and her team say it could benefit organic and conventional farms to be sufficiently separated for both.
But many farmers, both conventional and organic, are grappling with the idea of policies that could restrict where different methods can be used. And some outside researchers said more studies were needed before policy recommendations could be considered. They noted that the study did not measure the type or number of insects on the different farms, meaning that the increased use of pesticides may have been just a precaution.
Still, the “remarkable data set” makes the study useful for generating meaningful questions about farming practices and pesticides, said Christian Krupke, who studies insects as a professor of entomology at Purdue University and was not involved in the study. The overall number of insects is declining, a phenomenon some scientists have called the “insect apocalypse,” but pesticide use is not, he said.
Krupke said the research shows how ordinary farmers treat nearby organic operations “as a focal point of potential outbreaks.”
David Haviland, an entomologist at the University of California who was also not involved in the study, agreed. He described the fight in Kern County to control the glass winged maggot, which infests citrus orchards and can bring devastating plant diseases into grapes, almonds and some other crops. Haviland said that regional maps clearly show organic farms as “these big, incredible spots where there are large numbers of these pests.” Traditional growers next door have to increase their use of pesticides as a result, he said.
Yichao Rui, an agroecologist at Purdue, said that kind of response from farmers isn’t always due to an actual increase in pests; sometimes, it’s just “peace of mind.” And Katy Rogers, who manages an organic farm outside of Indianapolis, said it’s a misconception in many cases that organic farmers are harboring massive pest infestations.
“On most organic farms, on a well-managed farm, we’re not sustaining populations of harmful insects,” she said. “We’re just fighting them with other tools first. Because the bad bugs would still destroy my crop.”
Rui said that investigating the environmental consequences of organic farming is a worthwhile goal, and that both organic and conventional farms have room for improvement. But he thinks looking at pesticide use alone doesn’t take into account factors such as human health, air and water quality and ecosystem diversity that can be affected by different farming methods.
“We need to holistically assess the benefits and trade-offs of all these agricultural practices,” he said.
Brad Wetli, an Indiana farmer who normally farms corn, said he hasn’t noticed a change in his pest control situation since his neighbor switched to organic four years ago. He thinks it might be faster for farmers to put more pesticides on high-value crops like California’s fruits, vegetables and nuts, but not as much per acre as the row crops that grow it like corn and beans, so it would be necessary. a big change in the number of insects he saw on his farm before he got around to spraying more.
Wetli was more concerned with soil management. He is careful to plant cover crops and has worked to reduce tillage, which can cause soil erosion and pollute waterways, and he said organic farming still sometimes involves tillage.
Meanwhile, organic farmers expressed concern that the study addresses the impact of organic farms on conventional farms but not the other way around. For example, they can lose their certification for up to three years if a banned substance is applied to their fields, even if by accident, according to the USDA.
Walter Goldstein, a corn breeder in Wisconsin who produces both organic and inorganic seeds, grew up working on an organic farm among conventional farms and still remembers the flow of pesticides.
“It’s just these really weird smells,” he said. “Chemical smell. they smell like factory stuff.”
Jay Shipman, who owns an organic farm in Kern County next to another large organic farm, said he likes farming next to someone with similar practices “not just because it’s economics,” he said, but because ” this is how i eat. This is how I want my family to eat.” However, he said he grew up in conventional agriculture and understands that it can be “difficult to change, and hard to swallow to convince farmers that they should do something else.”
Rogers, an Indianapolis organic farm manager, spent much of her life in conventional agriculture and says she was taught that organic farmers are “the enemy.” She is now very dedicated to a small organic and regenerative farm run by a church with vegetables, beehives and hay.
Rogers said she can see benefits from clustering organic farms together, but she thinks dividing organic and conventional farmers as the researchers suggested could be “more polarized.”
“At the deepest level, we are all stewards of land and we all want to contribute,” she said.
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