Insect Control: Earworms, Beware!

New technology broadens the insect spectrum to
include corn earworms.

By Carroll Smith

The gently rolling hills and fertile creek and river bottoms of Henderson County, Tenn., form the backdrop for several successful grain farms. Stephens Farm is one of them. Gerald Stephens and his father, Wayne, are partners in a corn and soybean no-till rotation enterprise and also run a feeder calf, pre-conditioning and finishing operation.

“Corn is a vital part of the rotation on the crop side, but we also use a decent portion of the crop to provide feed and nutrition for our cattle,” Stephens says.

The father-and-son team crop about 2,600 dryland acres, which they have had in a no-till system for about 10 years. They like to keep the acres split 50-50 between corn and beans, although this year because of the extremely wet spring, their corn acreage was lower than normal.

Stephens describes the soil types on the farm as very variable. They farm in creek and river bottoms where there is quite a bit of sand as well as some heavy clays. The Stephens try to plant everything into a cover crop, which creates a heavy residue situation as opposed to other farmers who employ minimum till or lightly work the soil.

“We use cover corps to help retain moisture as well as feed the soil organisms that will translate into nutrition for the crop,” he explains. “We spray all of our corn with a fungicide since we farm in the bottoms and tend to have more disease pressure from the heavy moisture and humidity in the bogs.”

Earworms Not Fond Of New Hybrid
The Stephenses purchase their seed corn from Helena Chemical Co. in Jackson, Tenn., and this year they planted DeKalb hybrid corn exclusively – different hybrids within DeKalb, but strictly DeKalb genetics. Their corn yields typically range from 150 to 200+ bushels per acre.

One of the hybrids they agreed to try on about 40 acres was the new Genuity VT Triple PRO corn. According to Monsanto, “Genuity VT Triple PRO corn provides a broader spectrum of insect control against corn earworm, corn borer and fall armyworm, resulting in higher yield potential and better grain quality.”

To test the efficacy of the VT Triple PRO against earworms, in every field where he planted the new hybrid, he also planted hybrids that did not contain the additional gene to get a true side-by-side comparison.

“You could actually walk out into the field and see that there was no earworm damage on the Triple PRO corn where there was some damage on the other hybrid that was planted right next to it,” Stephens says. “We saved on insecticide cost because we did not spray any insecticide on the Triple PRO corn. There was no reason to because the earworm was not there.

“When the corn earworm comes through the shuck on the other hybrids, the kernels show signs of mold and degradation. Any time you have mold, it will lower the test weight and, ultimately, decrease yields,” he adds. “In fact, in really late-planted corn, earworms can take down yields by 10, 15 or even 25 bushels, depending on when the corn was planted.”

Tennessee Farm’s Post-Harvest Report
Like many other farmers in the Mid-South, corn harvest on Stephens Farm was affected by excessive rainfall that plagued the region. The Tennessee farmer says as the rain continued, mold continued to be even more of a problem on the corn that had worm damage.

“We harvested our corn at 23 percent moisture and saw a substantial difference in quality between the VT Triple PRO – which was much better – and the other hybrids,” Stephens says. “We also realized a yield increase, but we were particularly impressed with the quality.”

As far as his plans for the 2010 season, Stephens says, “I’m excited about the VT Triple PRO technology and plan to use it on many of our corn acres next year.”