Invasive species of snail adversely affecting crawfish, rice crops in Louisiana

Updated: Jul. 23, 2020 at 5:38 PM CDT
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BATON ROUGE, La. (WAFB) - A foreign, invasive species of snail has infested a handful of fields in southwestern Louisiana, forcing some farmers to reseed entire rice crops and scale back crawfish production.

The Apple Snail eats at young rice plants and thrives in moist environments. Farmers say the snails are clogging their crawfish traps, forcing workers to sort through their catches so snails are not sold with the mudbugs.

“They’ve cost us quite a bit of money and a lot of extra effort over time,” Kaplan farmer Christian Richard said. “Our guys do a good job. It just takes them twice as long to run traps. So if a guy is half is productive, that definitely affects the bottom line as well.”

In just two days, Snails decimated a 100-acre crop of rice on Richard’s farm. He had to start the crop over, reseeding at roughly $150 per acre.

“There’s not much of a way to combat them that doesn’t adversely affect the crop that we’re growing,” Richard said. “They seem to love water and if you’re growing rice and you’re growing crawfish - these fields are flooded.”

The Louisiana Department of Agriculture and Forestry (LDAF) says the apple snail first appeared in a bayou in Gretna in 2006 and quickly infested ponds, bayous, and streams in about 30 parishes across the state. The LSU AgCenter says the snail has impacted crawfish farms in Vermilion, Acadia, and Jefferson Davis parishes.

“People would buy these snails for their fish tanks and once they got too big, they would dump them in a local body of water where they’d become established and spread,” LSU AgCenter pest researcher Blake Wilson said.

Wilson said 2016 floodwaters probably carried the snails to farms from the infested Vermillion River.

A single female apple snail can produce up to 10,000 offspring each year. They lay their eggs in bright pink clusters on the stalks of the rice plants they eat.

“The eggs are laid at night so you can knock them all off and come back in the morning and there will be more eggs to replace,” Wilson said.

The eggs contain a neurotoxin that irritates the eyes and skin. The snails host the Rat Lungworm parasite that can inflame the tissue around the human brain if consumed.

Farmers can take precautionary measures to prevent infestation by using a dry seeding method. Experts are also checking irrigation systems that farmers often share to ensure the mollusks are not sprayed into new fields during watering.

Once the snails infest a farm, they’re almost impossible to get rid of. Pesticides that kill the snails would also kill the crawfish.

“From what I can see, where they’ve already become established, it’s not going to be a problem that can be eliminated,” Wilson said. “These farmers are going to have to learn to live with it. But we want to limit the number of farms and acres in the state that are impacted.”

LDAF says back in March, the snails reportedly wiped out a 50-acre field of rice, marking the first reported case of the species damaging the crop in Louisiana.

“It is imperative that each of us works diligently to protect Louisiana from these pests. Pests often find their way into the ecosystem by people releasing aquatic animals and ornamental plants in areas they should not,” said LDAF Commissioner Mike Strain, DVM. “I urge everyone to be mindful of the damage that can be done when non-native pests and plants are introduced into the environment. Take the giant salvinia, for example. It is an exotic fern from South America that is fast-growing and has wreaked havoc on lakes and ponds by destroying native plants that provide food for animals and also clogs the waterways.”

For more information about invasive species, click here, or call 225-952-8100.

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