On the Defense

March 27, 2010 06:56 AM

Controlling the pests in your fields takes a multipronged approach. Amid persistent pest pressure, the Farm Journal Test Plots have gathered in-field experience with evolving combinations of traits, pesticides, seed treatments and other pest controls.

The test plot effort focused on planter applications of controls for corn nematodes and corn rootworm.

"One pest we continue to have yield-robbing pockets of are corn nematodes,” explains Farm Journal Field Agronomist Ken Ferrie. "When we look at yield maps and NDVI [Normalized Difference Vegetation Index] photos, the yield loss due to nematodes is in the same general areas from year to year. They may be the size of a grain truck, a house or three to five acres.”

Ferrie says that working in central Illinois, it's not uncommon for him to see fields that average 230 bu. have their yields knocked back by 20 bu. to 50 bu. in the nematode pockets.

The test plots have specifically targeted corn nematode management since 2003. The controls used have included Mocap, Counter, N-Hibit and Syngenta's Avicta Complete Corn. We had three test plots in 2009 looking at different ways to manage nematodes. The plots included Counter, N-Hibit and Avicta Complete Corn compared with a check. We built on previous years' data with Counter and N-Hibit, but it was our first year to get in-field experience with Avicta.

"Results have been somewhat inconsistent,” Ferrie says. "Of all those that we've had multiple years' experience with, Counter has been the best performer despite its variability. Of the Avicta plots, one was inconsistent and two were positive.”

Of the two positive responses, Ferrie reports one field had a 4 bu. to 5 bu. response and the other responded up to 19 bu. At one farm, the plot crew could visually see improvement in root system and it showed up in yield.

"This past year we had a lot of water, so that made up for the root damage caused from the nematodes. These studies would be more consistent if we had dry or drought conditions that made the amount of root a premium,” Ferrie says.

Two factors drive our commitment to this ongoing effort.

"We need to continue this because, as our soil testing shows during the past 10 years, the nematode problem is getting considerably worse instead of better,” Ferrie says. "We haven't found a silver bullet, but we'll keep trying what's available on the market. Before it is a serious issue across the Corn Belt, we need to tackle the problem.”

Another insect pest the test plots have set their sights on is corn rootworm control. For the second year, we worked with John Deere and Syngenta to head to the field with a John Deere 1770NT planter with the Central Insecticide System (CIS).

The CIS planter allows for liquid Force CS insecticide to be centrally loaded for application with the planter. The system streamlines loading the planter with Force CS and requires the use of safety gloves. It also eliminates the chances of having to load granular insecticide on a windy day.

The plot included replicated passes in the trait corn and the refuge with the full rate of Force applied compared with untreated strips in both areas of the field. "With the insecticide
application, we saw a 6 bu. to 10 bu. yield response on the trait corn and the refuge,” Ferrie says.

This past year did not result in high rootworm pressures. With heavy and consistent rains, the rootworm pressures were considerably lower than the area has seen in previous years.
"This yield boost showed up even though we had low rootworm pressures and very little visible root damage,” he says. "This leaves us to believe the yield response probably came from managing secondary pests.”

Ferrie notes a couple of standout observations from this plot.

"There were two surprises in looking at the yield data from this study,” he says. "One was the response we got when there wasn't an obvious rootworm pressure. And the other is that the refuge corn without the insecticide outyielded the trait corn with the insecticide applied.”


You can e-mail Margy Fischer at mfischer@farmjournal.com.


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