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Published April 10, 2010, 12:00 AM

Bad news bugs

The two-striped grasshopper and the wheat stem sawfly are being watched closely by those at the state level, as they may cause producers in the southwest region some headaches this growing season.

The two-striped grasshopper and the wheat stem sawfly are being watched closely by those at the state level, as they may cause producers in the southwest region some headaches this growing season.

A federal survey of adult grasshoppers last fall indicated that parts of Wyoming, Montana, South Dakota, North Dakota, Nebraska and Idaho could face costly grasshopper infestations this summer, according to an Associated Press article.

A hot and dry spring could mean some hopper problems, said Janet Knodel, North Dakota State University Extension Service entomologist

“It’s mainly for rangelands and grasslands, but a couple of those species do cross over to the crops,” Knodel said, adding the two-striped and migratory grasshoppers are those that could cross over. “The bottom line is, they (producers) should get out early and scout.”

Grasshoppers are found across the United States, but outbreaks of pest species are most common in the Plains and Western states. Different species range from a length of under an inch to more than three inches.

Knodel said there has been a long history of grasshopper problems, especially in the western and central portions of the state.

“There’s quite a few different species of grasshoppers and they don’t all emerge at once,” Knodel said. “They have a real long, gradual emergence all the way from late May all the way out to early July.”

Grazing management on rangelands can help control grasshopper populations, according to a report written by Dr. Lee Manske, NDSU Dickinson Research Extension Center range scientist.

In his report, Mankse said the favorable habitat conditions can result from heavy grazing pressure, drought, and poorly timed grazing periods that do not allow grass plants time to recover from defoliation.

Large, adult grasshoppers can eat quite a bit of foliage and require a higher rate of insecticide, Knodel said.

Another major concern again this year includes the wheat stem sawfly, which had record high levels last year.

Sawfly feed internally on the wheat stem, interfering with the flow of water into the developing wheat head, resulting in smaller kernels and lower yield.

“It was a huge problem last year,” Knodel said. “We estimate it cost North Dakota overall anywhere from $20 million to $60 million.”

Research has shown it takes only 10 percent of that population level to survive over winter in the soil for the next year to cause that same level of population, she said.

Scranton-area producer Bruce Freitag said sawflies have affected the area for quite a few years.

“Some years are worse than others,” Freitag said. “I would say last year, even though there were high numbers of sawfly spotted, we didn’t see probably as much damage as we’ve seen here two or three years ago.”

Insecticides do not control sawfly, and the agency recommends producers use solid-stem variety wheat, Knodel said.

To help cope with the insect, Freitag said he does crop rotation, and for the past few years has planted durum, which is a little more resistant to sawfly damage than some of spring wheat varieties.

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