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Wheat Midge Levels Drop to Record Lows for 2013

wheat, wheat midge, Velva Hard Red Spring Wheat

Submitted by Craig Askim, Extension Agent/Agriculture and Natural Resources

Soil samples in North Dakota indicate low levels of overwintering wheat midge larvae (cocoons) for the 2013 season, according to Janet Knodel, North Dakota State University Extension Service entomologist.

"With the majority of soil samples statewide being low risk for wheat midge infestation, insecticides should not be needed for controlling wheat midge in 2013," she says. "However, we still recommend field scouting for wheat midge even with low populations to ensure that wheat midge will not reduce wheat yields, grade and quality."

A total of 199 soil samples were collected from 21 counties to estimate the regional risk for wheat midge. The distribution of wheat midge in the 2013 forecast map is based on un-parasitized cocoons found in the soil samples collected in the fall of 2012.

Wheat midge populations ranged from zero to 786 midge larvae per square meter, with an average of 34 larvae per square meter in 2012. In contrast, wheat midge populations ranged from zero to 1,879 midge larvae per square meter, with an average of 171 larvae per square meter in 2011.

"The decrease in wheat midge can be attributed to the drought, which may have prevented wheat midge larvae from dropping out of the wheat heads in late summer," Knodel says. "Moisture (rain or dew) triggers mature larvae to drop to the soil surface, where they burrow in and form overwintering cocoons.  There were no areas where the cocoon populations exceeded 1,200 per square meter, which would have indicated they were at high risk for a wheat midge infestation in 2013.

Weather conditions prior to and during adult wheat midge emergence will play an important role in determining the amount of economic damage. Conditions that favor midge development and outbreaks include high soil moisture in late June, warm temperatures, calm winds and high humidity during egg laying in early July.

A degree day model is a good predictor of wheat midge emergence and can help time field scouting. It is available on the NDSU North Dakota Agricultural Weather Network website at http://ndawn.ndsu.nodak.edu/wheat-midgedd-form.html.

Field scouting is conducted at night when temperatures are greater than 59 degrees F and the winds are calm (less than 6 mph) during the heading to early flowering crop stages.

The wheat midge survey is supported by the North Dakota Wheat Commission.

Source: Janet Knodel, NDSU Extension Service entomologist, (701) 231-7915, janet.knodel@ndsu.edu

Velva Hard Red Spring Wheat

Velva, a new hard red spring wheat, is available for purchase this year. Developed by NDSU, Velva was released for increase in 2011. It has a broad adaptation to the spring wheat region of western North Dakota.

Field tests showed Velva outperforming in yield over most other cultivars adapted to Western North Dakota.  Velva is a semi dwarf cultivar with medium late maturity similar to Reeder and Faller. Protein and milling levels are slightly better than Reeder. An excellent disease resistant package has been bred into it. For more information visit www.ag.ndsu.edu/crops/guides.html or call me at the office.

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