'Tent' shows pest, drought tolerance

HARWOOD, N.D. -- If you're in an area of increasing corn rootworm, stacked-trait crop protection could come in handy, especially in a drought year. A "stress mitigation tent" in Cass County is designed to make that point visible evidence of the e...

HARWOOD, N.D. -- If you're in an area of increasing corn rootworm, stacked-trait crop protection could come in handy, especially in a drought year.

A "stress mitigation tent" in Cass County is designed to make that point visible evidence of the effect of VT3 technology reducing the damage of drought. The high-tech "tent" was installed under contract by Monsanto Co. on July 3 on a field connected to Peterson Farms Seed of Harwood, N.D. It's one of more than 30 tents of its type across the country, and the farthest north. Others can be seen on Monsanto plots near Morris, Minn., and Brookings, S.D.

The structure is clearly different -- a clear ceiling with open sides to allow air flow. A clear poly roof allows 97 percent of the light through, but protects the corn from rain so that varieties of corn can demonstrate their tolerance of drought, which is connected to resistance to corn rootworm.

Of course, when rootworms eats roots, drought affects the plants much faster.

The plot demonstrates two hybrids with various combinations of three stacked traits -- a Roundup Ready II and YieldGard Corn Borer combination; VT3 corn; and the Roundup II and Herculex Extra package. Combinations are repeated outside the tent.


Carl Peterson, had seen one of the tents at a field trial two years ago in Iowa and immediately inquired whether Monsanto would consider his seed company's demonstration areas for one of the tent sites.

"The fact that we have rootworm in our field is a huge advantage," Peterson says. "In a non-rootworm area, sometimes they have to 'seed' the (rootworm) eggs, which gets to be expensive."

Peterson and Mike Larson, the company's sales manager, say the field was chosen because it has been corn-on-corn for four years, and showed heavy corn rootworm pressure last year, confirmed by North Dakota State University entomologist.

There has been corn rootworm in North Dakota for 25 years but the infestation levels have typically not been high enough to show economic damage in most fields. As farmers become more intensive in corn production that could change, Larson says.

Northern corn rootworm has a "variant" form, Larson says. Normally, corn rootworms would lay eggs, and then pop up and die when the next year's soybean rotation was being grown.

But the "extended diapause" variant will lay eggs in a corn field one year, wait a year through the rotation of soybeans the next year, and then emerge in the following year to damage corn.

This variant is involved heavily in the eastern third of South Dakota and southwest Minnesota and is creeping up into southern counties in North Dakota.

"It's spreading out like an oil spill," Peterson says.


Peterson Farms Seed will include a plot tour of the tent at their July 31 field day. Monsanto is scheduling additional groups separately.

Peterson says the rootworm pressure is significant on the plot, which is heavier clay soils.

During last year's field days, on Aug. 1, corn that stood 10 feet tall had almost no root structure, he says. Meanwhile, a neighbor's corn to the west has very little damage because it is in a corn-bean-wheat rotation.

"If rootworm has a food source, they won't go outside of that," Larson says.

There was ample moisture in June, but he thinks it will show drought pressure in unprotected hybrids.

Adam Spelhaug, an agronomist with the company, says the variant is starting to creep into Richland County in North Dakota, but there are other spotty infestations even in central North Dakota, where irrigated corn is used for silage.

"It's all over the state, but it's just never been an economic issue," he says.

Peterson, a big believer in quantitative research, acknowledges the tent in and of itself does not constitute research.


"There will be some hand harvesting part of that plot to take data, but data from one location doesn't mean anything," he says. "But the fact that there are 30-plus of these tents around the country . . . you put that together and it has some meaning on a quantitative basis. The benefit to the grower from this demonstration will be qualitative -- they'll see that the ears are smaller and the plants are showing drought stress."

Larson notes that the VT3 tent demonstrations had some influence on a pilot program for crop insurance within the U.S. Department of Agriculture's Risk Management Agency. Beneficial crop insurance rates for corn hybrids grown with VT3 technology were approved for four states in 2008, including Minnesota. That will be extended to South Dakota in 2009.

Proving the benefit of this kind of seed technology could pave the way for similar insurance benefits as companies develop drought-resistant varieties, he says.

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