Win the Battle Against Potato Nematodes

potato nematode

Include Velum® Prime and Movento® in your nematode control program

Nothing gives potato growers fits more than nematodes. It’s a year-long battle to control multiple generations of these profit-robbers.

Nematodes multiply quickly and can have three to six generations a season with each generation lasting four-to-five weeks. Growers in Idaho may deal with three or four nematode generations a year, whereas Washington growers could face four-to-six generations because of the longer growing season.

The key to a successful potato crop starts with controlling nematodes preseason and at planting. According to Bayer Tech Service Rep Justin Luangkhot, suppressing nematodes early season helps keep them below economic thresholds until harvest. Ignoring them at planting can be devasting.

Potato nematodes like root-knot, root lesion and stubby-root can cause up to 90 percent yield loss, according to USDA APHIS research. Nematodes also cause blemishes or tuber abnormalities that affect the marketability of the crop.

“If you are trying to decide if you want to use a nematicide to control nematodes and you wait and you let the nematodes move into the plant, you've already lost the battle with them,” Luangkhot said. “Because once they've begun feeding and moved into the roots, they're already in the plant and the damage has already been done. Ideally, you want to provide plant protection before nematodes move into the roots.”

Root-Knot Nematodes

Nematodes attack roots throughout the year, reducing yield and decreasing tuber quality. Processors will reject an entire field of potatoes even if a single-digit percentage of potatoes have root-knot damage. Some restaurants, McDonald’s for instance, have a zero tolerance for potatoes with root-knot nematodes.

Luangkhot says there are two types of root-knot nematodes Pacific Northwest potato growers confront. “The two main species that we deal with are northern root-knot, which is Meloidogyne hapla. Then we also have Columbia root-knot, which is Meloidogyne chitwoodi.”

To manage root-knot nematodes, Luangkhot suggests that potato growers use a fumigant in the fall after potato harvest or in early spring prior to planting. Then he recommends an application of Velum Prime at-plant. “Use Velum Prime in-furrow at planting or first chemigation. It gives growers a different mode of action … You want to use Velum Prime with the fumigant because you can extend your window of suppression.”

Saad Hafez, a nematologist for the University of Idaho, recommends two Movento applications – one when the plant is 6 inches tall and then again at canopy closing – in his nematode control program. “Movento is a very good nematicide,” Hafez said. “It will suppress the root-knot.”
The unique characteristics of Movento allow it to move from roots to foliage to stop nematode reproduction in the plant and stop tuber damage. “Movento is the only nematicide that will kill the nematode in the plant,” Hafez added.

Lesion Nematodes

Lesion nematodes impact yield by feeding on roots. They make holes in the roots that allow fungi to enter, causing wilting and yield loss. “Once fungus gets in the roots, it spreads in the whole plant and has an effect on the transportation of water and nutrients in the plant, which is why you get a lot of wilting,” explained Saad Hafez, a nematologist for the University of Idaho.

Hafez said the best way to manage this problem is with a nematicide and fungicide to control the lesion nematode from damaging the root, thereby not allowing fungi such as Verticillium to enter the plant.

“In Idaho, we’ve been recommending the use of Velum Prime/Movento for lesion nematode,” Hafez said. “You can go with Velum Prime at planting in-furrow, and then come back with Movento. We’ve seen in our trial that the Velum Prime/Movento is very effective to improve and manage lesion nematode. And you get a significant yield increase from lesion nematode control.”

The combination of an early-season application of Velum Prime followed by two applications of Movento is called the V+M Solution. According to third-party research, the V+M Solution increases production by 82 cwt/A on average.

Stubby-Root Nematodes

Stubby-root nematodes can transmit tobacco rattle virus, which causes corky ringspot in potatoes. It causes deformities and damages the inside of the potatoes, resulting in lower tuber quality.

“You get a lot of knobby tubers, which are unmarketable,” Hafez said. “It’s even worse than root-knot for the marketing. If you have even 1 percent in your field, then the whole field gets rejected.”

Hafez says that stubby-root nematodes are not easy to control since they are very mobile in the soil and can reach a depth of two feet. “We try to get the [V+M solution] as early as we can to stop stubby-root nematode from affecting the tubers,” he said.

Crop rotation also helps lower stubby-root and other nematode pressure levels. Hafez encourages growers to use a nematicide on the rotational crop, when permitted, to help manage nematode populations in the soil.

Kamren Koompin of Koompin Farms in American Falls, Idaho, said that rotating potatoes with oilseed crops is one piece of his nematode management program. Velum Prime is another. “Velum Prime fits in really nicely, especially going after the lesion nematode and the connection to Verticillium wilt,” he noted.

Additional Control

In addition to nematodes, Movento and Velum Prime help growers control other potato pests and diseases. Movento protects against aphids, psyllids, two-spotted spider mites and wireworms, which also helps suppress a broad range of diseases associated with these pests, including potato leaf roll virus. With Velum Prime, growers also get suppression of diseases like white mold and early blight.

Bret Severe, a crop consultant with Nutrien Ag Solutions, Idaho, suggests using Luna Tranquility® with Velum Prime for better plant health. “Luna Tranquility is a very good fit with Velum Prime in a rotation for disease pressure. It builds up the barrier that’s going to be in the plant for better total plant health, plus it’s a very good fit for white mold and early blight,” he said.

“Luna Tranquility works with a total program that you put together with a grower where you start early … and continue to follow throughout the growing season. And using those Bayer products has definitely made for a positive return on investment for my growers,” Severe added.

Available Resources

For more insights on controlling nematodes and other yield-robbing diseases, contact your Bayer rep or visit

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