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Infestation of invasive snail species in Montana

Eastern Heath Snail
Posted at 6:34 AM, Jul 24, 2023

Cascade, Chouteau, and Judith Basin Counties have discovered an invasion of select populations of the Eastern Heath Snail.

“It's established. Now, there isn't much we're going to be able to do to try to eradicate it. Our efforts right now are to try to provide enough education and outreach to people so that when and if they are affected by this organism, they’re able to have some information to work with,” explained Gary Adams, State Plant Health Director for the USDA, APHIS, PPQ.

The Eastern Heath Snail is native to Europe and is believed to have been brought to North America by settlers, but it’s unclear how it migrated to Central Montana.

“Being a dry land snail, it does not like hot and dry weather, so it tends to what we call estimate hibernate, during the summer and across upland plants get away from the heat and seal off the shell and it can remain that way for a few hours, sometimes several months in the lab several years.” Research Scientist, Jeffrey Littlefield said for Montana State University.

Littlefield is studying a population of snails a quarter mile from the town of Belt. Through a trail camera, he’s been able to see the overnight activity of the snails and depending on temperature can vary their movements. Littlefield said that in his recent research, the snails can move upwards of a few yards per night.

Eastern Heath Snail in Montana
Eastern Heath Snail in Montana

The discovery of the Eastern Heath Snail in Montana was 12 years ago, and in research, it’s been proven that they cannot be visible on your land and go dormant for up to 10 years.

Cascade County Jim Larson, a landowner near Belt, had the snails on his land 11 years ago and currently has seen no sight of them. That doesn’t mean they won’t come back.

“I don't know how you control them if the weather doesn’t affect them. We don’t have a chemical that works very well and it's expensive. So how do you control these things?”

Larson is asking the same questions the agencies are asking. On the market is a molluscicide that has proven inefficient and extremely expensive. The Eastern Heath Snails are hitchhiking pests, that can latch on to hay crops, infest a hay field, or anything else for that matter. The best-known method of containment is to not contribute to further spread.

“If you check your equipment, check your campers, your pickups, any machinery or equipment that you're moving around, if you happen to see them, make sure you get them washed off with hot water or squish them so that you're not traveling and dropping them off on the way,” said Katie Hatlied, MSU Extension Agent for Judith Basin County.

If you notice a small white mollusk that resembles the Eastern Heath Snail, contact your local MSU Extension Office and they will point you in the right direction. The USDA will send out an agent to confirm if the snail has made it to your property.

The USDA also asks landowners to report a spread by clicking here. The federal and state agencies can monitor the spread and date submitted.