MSU Students Trap Worms To Help Understand Enemy In Montana’s Grain Fields

Montana State University students traveled thousands of miles, dug hundreds of holes and sorted through truckloads of dirt to trap worms this summer.

The messy life and long hours of a worm wrangler help pay their way through college, but they also benefit an MSU graduate student who is conducting several studies involving a growing enemy of Montana’s grain, said undergraduates Branden Brelsford, Bozeman, and Emily Rohwer, Forest Grove, OR.

Wireworms, the tiny white larvae that turn into click beetles, are second only to the wheat stem sawfly for insects that damage wheat and barley in Montana, said Anuar Morales-Rodriguez, Department of Plant Sciences and Plant Pathology doctorial candidate. Wireworms also eat sugar beets, potatoes, lentils and other crops they encounter underground.

“We are losing several acres every year. They are taking out great big patches in the field and costing us considerable yield,” said Richard Barber, Denton, referring to his seed production fields for spring wheat, winter wheat and lentils.

Mark Grubb, Conrad, said he saw barren spots around the farm even when he was a young man working for his father, but, the problem worsened exponentially after he joined the Conservation Stewardship Program and instituted no-till practices on irrigated crops. The most significant damage occurred in his barley fields, but wireworms also invaded his winter wheat and spring wheat.

“It’s pretty much farm-wide now,” Grubb said.

Brelsford and Rohwer trapped wireworms in Barber’s and Grubbs’ fields this summer, as well as in other private and MSU fields around Montana. Supervised by Morales-Rodriguez in Kevin Wanner’s laboratory, Brelsford and Rohwer generally ran their trap lines twice a week. They left Bozeman at 5 a.m. and headed for fields as far away as Kalispell where they dug holes about 10 inches deep, set their traps and emptied previously set traps into plastic bags. They returned home the same day with their quarry still in the dirt.

Sorting through the bags revealed what they’d captured, the students said. Sometimes they found wireworms that almost fooled them into thinking they were roots. Occasionally, they came across beetles the size of their palms. They carried those across the hall to show international beetle expert Michael Ivie, who collaborates with Wanner. They also picked out spiders, decomposing earthworms and germinating seeds. The seeds, like any living organism, emit carbon dioxide which attracts the wireworms.

Morales-Rodriguez, a Colombian native who came to MSU because his research interests meshed with Wanner’s, said Brelsford and Rohwer probably traveled 10,000 miles this summer and captured 2,000 worms so far. That’s more worms than Montana producers want to see, but five times less than Morales-Rodriguez needs for his studies. He blamed the shortage on spring flooding, which sent the wireworms deeper underground, and said he has postponed some of his experiments because of it.

Morales-Rodriguez’ dissertation is focused on the management of wireworms in Montana’s wheat and barley fields. Describing his other research projects, Morales-Rodriguez said one study acquires basic information about the wireworms that live in Montana. The United States has 885 species, and 195 live in Montana, but they all look alike, he said. One way the MSU team is telling them apart is by analyzing their DNA supported by traditional taxonomy.

“With our work, we also want to link specific wireworm species to their adult counterparts,” Morales-Rodriguez said.

Scientists know a lot about click beetles, but not nearly as much about wireworms, the immature stage of click beetles, he said. Working with him on that is Frank Etzler, Buffalo, NY, a master’s degree student in entomology. Etzler works in Ivie’s lab.

Morales-Rodriguez is also evaluating the effectiveness of biological controls, such as bacteria and fungus, against wireworms. He is conducting experiments to see which chemicals work best. He said lindane was highly effective, but the insecticide can no longer be used in agriculture. The U.S. Environmental Protection Agency started restricting its use in the 1970s and completely banned it for agriculture in 2007.

Morales-Rodriguez is analyzing four types of traps, as well. Brelsford and Rohwer currently use all four traps to capture their worms.

In another project, Morales-Rodriguez is conducting a wireworm survey in conjunction with Wanner and MSU Extension. Participating producers request traps from MSU, set the traps in their grain fields and send the contents to MSU.

“We don’t really know too much about the life cycle and all the biological manifestations of wireworms in Montana,” Morales-Rodriguez said. “We assume their life cycle is three to five years, but some people report seven years.”

Morales-Rodriguez said wireworms live all over the world, and only some species cause problems. In fact, they often eat other insects that might be considered pests. But everything changes when the wireworms encounter agricultural land and do what comes naturally – eat. Then they become pests themselves.

As he tries to understand how wireworms function in Montana, Morales-Rodriguez said he appreciates the help he’s gotten from all his collaborators, including Rohwer and Brelsford.

“They are really, really good workers and hard workers,” he said of the worm trappers.

Rohwer is a senior in biotechnology (microbial systems). Brelsford is a sophomore in pre-med. Both said they enjoy research. Brelsford added that he likes the fact that the wireworm projects often send him outdoors.

Others working with Morales-Rodriguez are scientists at MSU’s Agricultural Research Centers – particularly John Miller and Grant Jackson, Conrad, and David Wichman, Moccasin. MSU Extension Agent Dan Picard, Conrad, is involved, as well.

Funding for the wireworm research comes from the U.S. Department of Agriculture’s “Crops at Risk” program and from industrial support.