Impact of Giant Snails and Tiny Insects on Rice and Crawfish Farming
Josh Courville has harvested crawfish his whole life, but these days, he’s encountering a less welcome catch in the fields he manages in southern Louisiana.
Snails. Big ones.
For every crawfish Courville pulls from a trap, three or four apple snails clang onto the boat’s metal sorting table. These snails, about the size of a baseball when fully grown, are resilient, surviving various weather conditions in fields, pipes, and drainage ditches. They can lay thousands of bubblegum-colored eggs every month.
“It’s very disheartening,” Courville said. “The most discouraging part, actually, is not having much control over it.”
Apple snails are just one example of how invasive species can quickly become a nightmare for farmers. In Louisiana, where rice and crawfish are often grown together, there’s now a second threat: tiny insects called delphacids that can inflict catastrophic damage on rice plants. Much about these snails and insects remains a mystery, and researchers are investigating what fuels their spread—from farming methods and pesticides to global shipping and extreme weather.
Experts are uncertain about the role of climate change, but they agree that a warming world generally facilitates the spread of pests to other regions if they gain a foothold in the temperate South.
“We are going to have more bugs that are happier to live here if it stays warmer here longer,” said Hannah Burrack, professor and chair of the entomology department at Michigan State University.
Inconvenience, stress, and higher costs for farmers
Courville manages fields for Christian Richard, a sixth-generation rice farmer in Louisiana. Both began noticing apple snails after a severe flood in 2016, and since then, the population has exploded.
During spring, at rice planting time, the hungry snails found a feast.
“It was like this science fiction movie,” Richard said, describing how each snail created its own little whirlpool as it emerged from the wet ground. “They would start on those tender rice plants, and they destroyed a 100-acre field.”
Louisiana State University scientists estimate that approximately 78 square miles (202 square kilometers) in the state now regularly see snails.
To prevent the rice from becoming a snail buffet, Richard’s team, along with many other rice and crawfish farmers, starts with a dry field to allow the rice plants to grow a few inches and strengthen before flooding the field. This method was already in use on some fields prior to the arrival of the snails, but now, it’s essentially their only option—and the most expensive one.
Eliminating the snails entirely is not feasible. Many pesticides that could work on snails also harm crustaceans. Since both rice and crawfish are directly consumed by people, farmers have fewer chemicals available for use. One option some farmers are testing, copper sulfate, can significantly increase operational costs, Courville noted.
This situation leads to “lower production, decreased revenue from that, and increased costs with the extra labor,” Richard explained.
Cecilia Gallegos, a crawfish harvester for the past three years, shared that the snails have complicated her job over the past year. “You give up more time,” she said, referring to the need to separate crawfish from snails or occasionally plucking them out of sacks if they accidentally roll in. Work that already stretched late into the night can now take even longer.
The snails separated from the crawfish are destroyed later.
One of the most significant pest appearances since the 1950s
To search for pests much smaller than the apple snails, entomologists use heavy-duty butterfly nets and Ghostbusters-style specimen-collecting vacuums. Since last year, they’ve been sampling for rice delphacids, tiny insects that pierce rice plants, suck out their sap, and transmit a rice virus that exacerbates the damage.
This situation is concerning for Louisiana, especially given the severe impact seen in Texas, where delphacids surged last year. Yields dropped by up to 50% in the ratoon crop, the second rice crop of the year, according to The Rice Foundation’s Linscombe. Texas farmers are projected to cultivate rice on only half the acres they did last year, and some are worried about securing bank loans, said Tyler Musgrove, a rice extension specialist at the Louisiana State University AgCenter.
Musgrove noted that entomologists believe almost all rice fields in Louisiana had delphacids by September and October of last year. By that time, most of the rice had already been harvested, leaving farmers anxious about the upcoming season.
“The rice delphacid this past year was probably one of the most significant entomological events to occur in U.S. rice since the ’50s when it first appeared,” Musgrove stated. Delphacids had eventually disappeared after that outbreak until now. They have been identified in four of the six rice-producing states—Texas, Louisiana, Arkansas, and Mississippi—but it remains unclear whether they have established a permanent winter home in the U.S.
Scientists are still in the early stages of advising farmers on how to address the resurgence of these destructive bugs without resorting to costly or crawfish-harming pesticides. They are also beginning to study whether rice and crawfish grown together will experience different impacts compared to rice grown alone.
“I think everyone agrees, it’s not going to be a silver bullet approach. Like, oh, we can just breed for it or we could just spray our way out of it,” said Adam Famoso, director of Louisiana State University’s Rice Research Station.
Climate change makes it harder to plan around pests
Burrack from Michigan State noted that climate change complicates the modeling that has traditionally helped predict how large populations of invasive pests will grow and when they may impact specific crops. This unpredictability makes it increasingly difficult for farmers to plan effectively.
“From an agricultural standpoint, that’s generally what happens when you get one of these intractable pests,” Burrack explained. “People are no longer able to produce the thing that they want to produce in the place that they’re producing it.”
Copyright 2026 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
Topics
Agribusiness
Josh Courville has harvested crawfish his whole life, but these days, he’s encountering a less welcome catch in the fields he manages in southern Louisiana.
Snails. Big ones.
For every crawfish Courville pulls from a trap, three or four apple snails clang onto the boat’s metal sorting table. These snails, about the size of a baseball when fully grown, are resilient, surviving various weather conditions in fields, pipes, and drainage ditches. They can lay thousands of bubblegum-colored eggs every month.
“It’s very disheartening,” Courville said. “The most discouraging part, actually, is not having much control over it.”
Apple snails are just one example of how invasive species can quickly become a nightmare for farmers. In Louisiana, where rice and crawfish are often grown together, there’s now a second threat: tiny insects called delphacids that can inflict catastrophic damage on rice plants. Much about these snails and insects remains a mystery, and researchers are investigating what fuels their spread—from farming methods and pesticides to global shipping and extreme weather.
Experts are uncertain about the role of climate change, but they agree that a warming world generally facilitates the spread of pests to other regions if they gain a foothold in the temperate South.
“We are going to have more bugs that are happier to live here if it stays warmer here longer,” said Hannah Burrack, professor and chair of the entomology department at Michigan State University.
Inconvenience, stress, and higher costs for farmers
Courville manages fields for Christian Richard, a sixth-generation rice farmer in Louisiana. Both began noticing apple snails after a severe flood in 2016, and since then, the population has exploded.
During spring, at rice planting time, the hungry snails found a feast.
“It was like this science fiction movie,” Richard said, describing how each snail created its own little whirlpool as it emerged from the wet ground. “They would start on those tender rice plants, and they destroyed a 100-acre field.”
Louisiana State University scientists estimate that approximately 78 square miles (202 square kilometers) in the state now regularly see snails.
To prevent the rice from becoming a snail buffet, Richard’s team, along with many other rice and crawfish farmers, starts with a dry field to allow the rice plants to grow a few inches and strengthen before flooding the field. This method was already in use on some fields prior to the arrival of the snails, but now, it’s essentially their only option—and the most expensive one.
Eliminating the snails entirely is not feasible. Many pesticides that could work on snails also harm crustaceans. Since both rice and crawfish are directly consumed by people, farmers have fewer chemicals available for use. One option some farmers are testing, copper sulfate, can significantly increase operational costs, Courville noted.
This situation leads to “lower production, decreased revenue from that, and increased costs with the extra labor,” Richard explained.
Cecilia Gallegos, a crawfish harvester for the past three years, shared that the snails have complicated her job over the past year. “You give up more time,” she said, referring to the need to separate crawfish from snails or occasionally plucking them out of sacks if they accidentally roll in. Work that already stretched late into the night can now take even longer.
The snails separated from the crawfish are destroyed later.
One of the most significant pest appearances since the 1950s
To search for pests much smaller than the apple snails, entomologists use heavy-duty butterfly nets and Ghostbusters-style specimen-collecting vacuums. Since last year, they’ve been sampling for rice delphacids, tiny insects that pierce rice plants, suck out their sap, and transmit a rice virus that exacerbates the damage.
This situation is concerning for Louisiana, especially given the severe impact seen in Texas, where delphacids surged last year. Yields dropped by up to 50% in the ratoon crop, the second rice crop of the year, according to The Rice Foundation’s Linscombe. Texas farmers are projected to cultivate rice on only half the acres they did last year, and some are worried about securing bank loans, said Tyler Musgrove, a rice extension specialist at the Louisiana State University AgCenter.
Musgrove noted that entomologists believe almost all rice fields in Louisiana had delphacids by September and October of last year. By that time, most of the rice had already been harvested, leaving farmers anxious about the upcoming season.
“The rice delphacid this past year was probably one of the most significant entomological events to occur in U.S. rice since the ’50s when it first appeared,” Musgrove stated. Delphacids had eventually disappeared after that outbreak until now. They have been identified in four of the six rice-producing states—Texas, Louisiana, Arkansas, and Mississippi—but it remains unclear whether they have established a permanent winter home in the U.S.
Scientists are still in the early stages of advising farmers on how to address the resurgence of these destructive bugs without resorting to costly or crawfish-harming pesticides. They are also beginning to study whether rice and crawfish grown together will experience different impacts compared to rice grown alone.
“I think everyone agrees, it’s not going to be a silver bullet approach. Like, oh, we can just breed for it or we could just spray our way out of it,” said Adam Famoso, director of Louisiana State University’s Rice Research Station.
Climate change makes it harder to plan around pests
Burrack from Michigan State noted that climate change complicates the modeling that has traditionally helped predict how large populations of invasive pests will grow and when they may impact specific crops. This unpredictability makes it increasingly difficult for farmers to plan effectively.
“From an agricultural standpoint, that’s generally what happens when you get one of these intractable pests,” Burrack explained. “People are no longer able to produce the thing that they want to produce in the place that they’re producing it.”
Copyright 2026 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
Topics
Agribusiness
