Corn Rootworm Knowledge Research Program grows to meet needs

2013-10-03T08:47:00Z Corn Rootworm Knowledge Research Program grows to meet needsBy ANDREA JOHNSON Assistant Editor Minnesota Farm Guide
October 03, 2013 8:47 am  • 

A new initiative from Monsanto is assuring that high-level research occurs to study the corn rootworm.

Dubbed the Corn Rootworm Knowledge Research Program, Monsanto established the program in 2012 with a $3 million pledge. They just announced they would contribute an additional $3 million.

This program is significant to researchers as each project can receive up to $250,000 per year for three consecutive years to reach a total of $750,000.

The awards are large enough and run for a long enough time to support the work of graduate students.

“Researchers want to get these long-term commitments, because they are hiring students, they are hiring post-docs, and they don’t want it to be a one-year commitment – especially when you’re trying to do field studies and crops. You really need multiple years to validate the data,” said Dusty Post, Monsanto vice president of Global Insect Management systems. Post is co-chair of the CRW Knowledge Research Program.

Six projects (out of 32 applications) received funding in 2012, and work began this year on the projects. The work is considered public – not for the sole use of any one company.

“Our intent is to develop a better and broad understanding of corn rootworm that will not only be beneficial to the seed industry, but to the grower and to the academic world as well,” Post said. “We feel the research needs to be public to do that.”

From the University of Minnesota, Kenneth Ostlie, Ph.D. and Extension entomologist, received a three-year award to study, “Corn Rootworm Emergence, Scouting and Contemporary Thresholds for Field-Specific Management.”

The award was about $525,000. Like most grants coming into the University of Minnesota, the University receives a little less than half of the dollars for overhead expenses. Ostlie’s program receives a little over half to conduct research.

While Minnesota pays for Ostlie’s salary, he is not given any dollars for research. That means he has to rely on outside funding.

In general, Ostlie receives funding from companies looking for specific research. The Minnesota soybean, corn and wheat checkoffs also provide important funds provided on a year-to-year basis. Additional dollars come from the Minnesota Rapid Agricultural Response fund, and USDA grant programs.

Ostlie’s CRW Knowledge Research Program dollars will help finance salaries for undergraduate biology/ag students and staff working on the research, as well as Joel Braun, Master’s candidate and Trisha Franz, Ph.D. candidate.

“The CRW Knowledge Research Program is set up well from the standpoint of getting good science from it,” said Ostlie. “It’s not addressing a product-specific activity. It is dealing with broader issues.”

Ostlie’s study focuses on understanding the expanding geography of Western corn rootworm.

“Even as corn rootworms figure more prominently in crop management decisions, most growers are operating blind with little field-specific information on corn rootworm problems,” Ostlie said.

As a result, growers will often use an “insurance approach” to CRW control – that includes layering multiple tactics without necessarily using best management practices.

Getting more feedback on actual larvae counts, the potential for economic damage, managing rootworms and understanding the implications of resistance management could help growers make better decisions.

This in turn, could help save Bt-events, so these technologies will be available when and where they are most needed.

Ostlie’s research up to this point has documented CRW resistance to Bt traits in the laboratory and in Minnesota fields.

“We have verified that we have beetles that are resistant to traits,” he said. “It is confirmed we have the issue, and we also have cross resistance in Minnesota.”

The billion-dollar question

From larva to beetle, the corn rootworm is difficult to control.

Science has not yet figured out how they adapt quickly to new environments and overcome insecticides and other control methods – although selection pressure has a significant role in resistance.

“That could be the billion dollar question that we really don’t have a good answer,” said Post.

“We do know that some organisms, whether they are insects or bacteria or viruses or whatever, are very adaptable – they are able to mutate at a good rate,” she continued. “Corn rootworm is an outlier compared to other insects, in terms of its resistance mechanisms to a variety of things.”

Currently, Monsanto scientists are working toward sequencing the corn rootworm genome – outside of the CRW Knowledge Research Program. They are also trying to map and understand the nature of the genes that may be involved in resistance, she said.

Corn rootworm has been a serious pest for many years in Minnesota, North Dakota, South Dakota, Iowa, Nebraska, Illinois, Indiana and Colorado, said Tom Eickhoff, Monsanto Corn Systems lead, St. Louis.

“It has been a challenge to control and manage, overcoming various classes of insecticides in the past,” said Eickhoff.

The Western corn rootworm adapted to crop rotation by laying eggs in soybean fields. The Northern corn rootworm adapted to an extended diapause – staying dormant an extra year to be ready for corn in the corn/soybean rotation.

“This pest has evolved in many ways to circumvent or get around our management practices,” he said.

Recently, the Western corn rootworm has become more widespread and challenging to control. It is also an aggressive feeder, he said.

More important than geography, the impact of CRW depends on the amount of stress put on the corn plant.

If the corn plant has a small root mass, the CRW damage can lead to downed corn and a smaller ear. When the corn plant develops large roots, CRW may have less of an affect as the plant compensates.

“Managing stress within the crop is one of the keys to achieving high yields,” he said. “When you couple things like extreme weather events along with pest feeding, you compound the issue of managing stress within the crop. It will ultimately lead to yield impact.”

Eickhoff added that farmers in various regions of the Corn Belt have developed their own ways of dealing with CRW. In his experience, Western Corn Belt growers have aggressively used insecticides – both soil-applied and foliar. Eastern Corn Belt growers have used crop rotation plus soil-applied insecticide.

Growers across the Corn Belt have also adopted genetic traits to control CRW.

With its ability to mutate and adapt, CRW has overcome some of the valuable genetic traits in fields planted to corn at least three years in a row.

Ostlie pointed out that it is impossible to look at a lodged cornfield – that has traits – and know that CRW has adapted to the trait, of if something else is going on.

“Was it a planting mistake? Is the trait working like it is supposed to?

“Occasionally, conversion of a hybrid or the insertions of the genes may result in a hybrid that is not producing the level of protein that is required for good control,” he said. “There are a lot of quality control efforts that occur to make sure that doesn’t take place. Once in awhile, these are living organisms, so performance problems are related to the current situation.”

After these factors are removed, if the larva survives in the presence of the protein – that could indicate resistance.

“What we are apprehensive about, is if the resistance to these Bt traits gets coupled with resistance to crop rotation,” he said. “That puts a lot more corn at risk – not just corn-after-corn.”

As growers make their corn seed selections for 2014, Ostlie encourages them to remember that resistance occurs because one trait is selected over and over.

“The more intensely we use a tactic, the faster CRW is going to develop resistance,” he said. “That is the same for all traits. We know crop rotation at this point can work well for us, soil insecticides can provide some backstop for traits. The bottom line is we need to be concerned about CRW populations whenever we are growing corn-after-corn, using the same traits.

“The most critical thing growers can do for next year is to plan on how they are going to assess what CRW are doing in their fields.”

The corn community wants to see traited products maintain their value and protect corn.

“We are looking at CRW biology to understand the resistance, and we are looking at the genomics to understand the nature of the heritability of resistance,” said Post. “Hopefully, these two things will help us design better and more durable products in the future.”

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