PEMBINA, North Dakota — They lie hidden on shipping containers or inside trucks at the U.S. border, threatening to undermine the American way of life.

They are the likes of the khapra beetle, twirler moth and noxious weeds like hogweed.

But thanks to the work of agriculture specialists with the U.S. Customs and Border Protection, many are stopped before they can cross into the United States. They also make sure that load of hay isn't hiding some marijuana.

A truck hauling hay approaches the U.S. border with Canada at Pembina, North Dakota, on Monday, Nov. 15, 2021. Mondays are a busy day at the Pembina Port of Entry when neary 1,000 trucks might pass from Canada into the U.S. Trevor Peterson / Agweek

"When they go over to do inspections, it's basically manual labor," said Kristi Lakefield, a spokesperson for Customs and Border Protection in Portal, North Dakota, where inspecting containers shipped by rail is the primary duty.

Lakefield said the crossing at Portal is the fifth busiest railyard in the country when measured by number of containers. The crossing at International Falls, Minnesota, is the busiest. During fiscal year 2020, the International Falls Port of Entry cleared approximately 800,000 containers. During that same time, Portal cleared approximately 310,000 containers.

At Pembina, North Dakota, about 500 trucks might pass through from Canada on average day. On a busy Monday, it may be closer to 1,000.

The ag specialists look at pallets, at the bottom of containers and elsewhere for possible stowaways. Inspectors also look to see if a product matches what is listed on a shipping manifest. On Nov. 15, a truckload of grass seed from Germany was pulled into the inspection area at Pembina. An inspector cut open a bag to look for noxious weed seed.

Neil Halley became an ag inspector for Customs and Border Protection at Pembina, North Dakota, after a career in ag education. Jeff Beach / Agweek

"We find something about every other day," said Neil Halley, a Customs and Border Protection agricultural specialist at Pembina. Halley taught ag education in St. John, North Dakota, before joining the CBP.

To be an ag inspector, you must have a four-year degree in a science field such as biology, and then undergo special training with the U.S. Department of Agriculture.

An ag inspector at the Pembina Port of Entry on Monday, Nov. 15, looks through a sample of grass seed taken from a bag shipped from Germany. Ag inspectors look for noxious weed seeds in sample taken off trucks. Trevor Peterson / Agweek

If something suspect is found, Lakefield said a photo can be sent to a pest identifier for confirmation within the same day. Sometimes the physical sample needs to be sent for positive identification, which may require about a week to complete.

Meanwhile, the suspect containers are pulled off the train or truck to wait at the border. Sometimes a container may be able to fumigated and can then continue south. Other times, they are sent back into Canada and to the country of origin.

Some examples of the finds that ag inspectors make at the border include:

Pembina: Halley said inspectors have twice found the khapra beetle, what he calls one of the 10 most wanted insect in the world and which feeds on stored grain. An express courier shipment contained seeds of the giant hogweed, a noxious weed. Also found in the were cucurbit (gourd), brassica (cabbage), and buckwheat seeds. The shipment did not have the required seed certificates to enter the United States.

International Falls: Inspectors there intercepted a container with cerambycidae (longhorn beetle) and gracillarioidea (leaf blotch miner moth) and imperata cylindrica, a federal noxious weed. The container was re-exported to Taiwan.

This twirler moth is an example of the pest that can be found on containers at the U.S.-Canada border. Photo submitted by U.S. Customs and Border Protection

Portal: Gelechioidea, a twirler or curved-horn moth, was found within a shipment of steel wheels from Vietnam and the container was sent back there.

The steel shipment from Vietnam shows that it is not just ag shipments that can be suspect. Lakefield said containers, pallets or products stored outside before coming to Canada and the U.S. can carry weeds and pests. Used equipment or heavy machinery may be carrying infested clumps of dirt.

Lakefield said many of the containers have come through British Columbia in Canada before crossing the U.S. border.

"A lot of goods are from the Pacific Rim," she said. "When looking at a long chain of railcars crossing the countryside, "you don't really know the back story."

As vehicles funnel through the Pembina Port of Entry, the drivers and passengers may not know it, but all are scanned for radiation. Any shipment that rises about a certain threshold will be inspected. Some materials, such as potash, have a naturally occurring level of radiation and can still continue south.

The border agents also have another scanning tool available — a gamma ray scanner that functions something like a giant X-ray machine.

Some trucks are pulled into a metal building to be scanned. The driver exits to vehicle to a waiting area while scanners on tracks on either side go down the length of the truck, sending images to inspectors.

A random truck is pulled in for a gamma scan at the Pembina Port of Entry on Monday, Nov. 15. Scanners on tracks on either side of the truck provide images of what is inside to Customs and Border Protection. Jeff Beach / Agweek

Pembina Assistant Area Port Director Christopher Misson cited an example from the spring of 2021 when a load of hay came through in a container. The gamma ray scanner detected what he called an anomaly in the back third of the load. Upon closer inspection, that anomaly turned out to be marijuana. The case was then handed over to local law enforcement for prosecution.

Christopher Misson is the Pembina assistant area port director for Customs and Border Protection. Trevor Peterson / Agweek

Some trucks are pulled in for scanning at random and other times because inspectors, through training and experience, have become suspicious.

"Some things just jump out," said Misson, a Detroit Lakes, Minnesota, native.

The Pembina, North Dakota, Port of Entry. Trevor Peterson / Agweek After an initial screening at the Pembina Port of Entry, trucks hauling livestock are sent to USDA veterinarians before they an continue south on Interstate 29.

Mike Stepien, of the USDA's Animal and Plant Health Inspection Service, said animals headed for slaughter have a less rigorous inspection process at the port because they will have further inspections by USDA's Food Safety and Inspection Service, typically within a day or so of being imported.

Animals imported for breeding purposes will be more rigorously scrutinized because it is expected these animals will become part of the U.S. herd, Stepien said.

In addition to ensuring the animals are in general good health and aren’t exhibiting any signs of disease, Stepien said there are checks to make sure that required tests have been performed. To ensure traceability, the livestock must also meet the identification requirements for importation.

Vesicular lesions in swine, cattle being of an age to be at risk of bovine spongiform encephalopathy and farmed deer that don’t meet the brucellosis test requirement are common issues in livestock, Stepien said.

Halley said fresh meat is sent to an inspector in the town of Pembina, but that packaged meat is inspected by his staff. He said inspectors have sometimes found "bush meat" from Africa that can is prone to carrying disease.

“These agriculture seizures show the significant priority Customs and Border Protection places on our agriculture inspection program at our ports of entry,” Misson said.