NDSU Crop and Pest Report

Entomology


ISSUE 4   May 27, 2004

NDAWN: NORTH DAKOTA AGRICULTURAL WEATHER NETWORK -
Valuable Resource for Crop Production and Pest Management

http://ndawn.ndsu.nodak.edu/index.html  

Here is a little more information on this internet resource, already referenced by other contributors in earlier issues. There are 66 weather stations distributed across North Dakota and border regions of surrounding states. The locations are shown in the following figure.

Users can obtain 18 different weather variables from any or all of the individual stations or summaries from across the state. A specific range of dates can be designated.

The wheat growth model and the wheat midge models have been very useful in recent years. The NDAWN site allows a person to select a specific weather station, enter specific planting dates, and receive output that summarizes temperatures, wheat growing degree days, expected growth stage, risk to midge infestation based on growth stage, and midge emergence based on degree days.

NDAWN Wheat Growth Model Submission Options

NDAWN Wheat Midge Model Submission

The output you receive from the above example looks like this. In this example, this field of wheat should have been at an advanced growth stage where midge infestatation would not have been likely.

There is also an option to summarize midge degree day accumulations over the entire state, similar to the maps that have been provided in this newsletter in recent years.

People are encouraged to visit the NDAWN website to become familiar with models and information that is available. We are also interested in hearing feed back on how to improve the accessibility of the data, or ways to make it more useful, such as additional models that would be helpful. For questions, suggestions, and just to let us know you found the NDAWN site useful, you can contact:

Dr. John W. Enz, North Dakota State Climatologist
North Dakota State University; Soil Science Dept.
233 Walster Hall
PO Box 5638
Fargo, ND 58105
Phone: 701-231-8576
Fax: 701-231-7861
john.enz@ndsu.nodak.edu

Phillip Glogoza
Extension Entomologist
pglogoza@ndsuext.nodak.edu

 

SUGARBEET ROOT MAGGOT:

First flies observed, peak activity still a few weeks away

A couple of sugarbeet root maggot flies found their way into a rain gauge at the NDSU research plots southwest of St.Thomas, ND, although none have been actually captured on sticky-stakes yet. Air temperatures have been generally below normal for much of the region, and areas in the extreme northern end of the Red River Valley that received significant late-Spring snow accumulations are slightly more behind normal. Surprisingly, soils in the central and southern Valley are not exceptionally low in degree day (DD) accumulations compared to last year at this time.

Peak activity in current-year sugarbeet fields is not expected for a few weeks yet, but it is important to note that a stretch of several warm sunny days can warm the dark Valley soils up and accelerate maggot development. Watch for updates on the root maggot forecast in the next few issues of Crop & Pest Report.

 

RESCUE INSECTICIDES MAY BE NEEDED FOR ADDED PROTECTION FROM SUGARBEET ROOT MAGGOT

Although many Red River Valley sugarbeet fields were planted somewhat early this year, below-normal temperatures and a general lack of soil moisture prevailed in much of the production area after planting. Seedling development is currently behind normal in many fields, and those sugarbeet plants will be especially vulnerable to attack from the sugarbeet root maggot. Fields in low-level risk areas (central and southern areas of the Valley) should be adequately protected if a planting-time soil insecticide was used. However, growers in areas of anticipated high maggot populations should be especially wary of the potential for major injury in their fields. If less than the full labeled insecticide rate was used at planting, a postemergence application will probably be needed for adequate protection.

Soil moisture and the severity of fly population levels should be considered in choosing whether to use a liquid or a granular formulation. Granular materials usually perform better if applied slightly before anticipated peak fly activity and liquid products provide the best activity if applied within three days (either before or after) of peak. Postemergence granules are more effective under moist soil conditions or if applied within a few days prior to a rainy period. Granules are advised in fields that have been re-seeded without a second planting-time insecticide. Liquid insecticides will perform better than granules if soil conditions are dry. A liquid formulation of an organophosphate such as Lorsban 4E may provide some larval control in addition to killing adult flies, especially if rainfall is received within 1 or 2 days of application to incorporate it into the soil. Liquid insecticides also may be useful if an unusually high flare-up of fly activity occurs. Research suggests that adult fly control can also be achieved with Asana; however, neither it nor other pyrethroid products will not be particularly active against larvae when applied postemergence. Refer to the "Insect Control" section of the 2004 Sugarbeet Production Guide or the "Sugarbeet Insects" section of the 2004 Field Crop Insect Management Recommendations for more detail and specific product recommendations. The respective WWW locations for online versions of these publications are:

http://www.sbreb.org/Production/production.htm

and

http://www.ext.nodak.edu/extpubs/plantsci/pests/e1143w1.htm  

Mark Boetel
Research & Extension Entomologist
mboetel@ndsuext.nodak.edu


NDSU Crop and Pest ReportTop of PageTable of ContentsPrevious PageNext Page