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2018 IPM Survey Results – Small Grain (08/30/18)

The purpose of the IPM (Integrated Pest Management) Survey is to detect the presence and population levels of diseases and insect pests that are common in wheat and barley grown in North Dakota.

2018 IPM Survey Results – Small Grain

The purpose of the IPM (Integrated Pest Management) Survey is to detect the presence and population levels of diseases and insect pests that are common in wheat and barley grown in North Dakota. Ten survey scouts or insect trappers operated out of the Dickinson Research Extension Center, the North Central Research Extension Center (Minot), the Carrington Research Extension Center, the Langdon Research Extension Center, the Williston Research Extension Center and the Fargo Agricultural Experiment Station. The NDSU IPM scouts were:

  • Brittney Aasand, central and south central counties, worked out of Carrington REC with Greg Endres
  • Marc Michaelson, southwest and west central counties, worked out of Dickinson REC with Ryan Buetow
  • Caleb Cross and Bree Obergfell, north central counties, worked out of NCREC in Minot with Travis Prochaska
  • Scott Roseth and Jace Paryzek, northwest counties, worked out of Williston REC with Audrey Kalil
  • Dan Kraemer and Stafford Thompson, southeast and east central counties, worked out of NDSU campus, Fargo with Jan Knodel, Andrew Friskop and Sam Markell.
  • Kaylee Anderson and Traci Murphy, northeast counties, worked out of Langdon REC with Leslie Lubenow and Benson County Extension Office with Scott Knoke

NDSU IPM field scouts surveyed a total of 1,385 wheat fields (winter wheat, hard red spring wheat, durum wheat) and 105 barley fields for 18 diseases and 6 insect pests of North Dakota in 2018. The survey was initiated on June 4 and continued through August 10. Crops were surveyed from the 2-leaf stage through ripening stages. IPM survey data/maps provide near real-time pest information to North Dakota producers and others in agriculture to assist with scouting and pest management decision making. Pest maps from the 2018 IPM Survey in North Dakota were uploaded weekly onto the NDSU IPM website. Some of the pest highlights for wheat and barley are summarized next.

Insect Pests:

Grasshoppers – Adult grasshoppers were observed in 75% of the fields surveyed. This was an increase from last year’s incidence with only 36% of fields surveyed reporting grasshoppers. The number of grasshoppers per 4 sweeps (1 yd2) ranged from 1 to 25. The hot and dry weather conditions during August favored late season grasshopper infestation; however, most fields only had feeding damage on field edges. Grasshopper ‘hot spots’ in 2018 included Benson, Bottineau, Renville and Ward Counties.

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Grain aphids were very low and observed in only 3% of the wheat fields and 8% of the barley fields surveyed in North Dakota. Grain aphids were first detected on June 19 and populations never developed economic levels (85% of stems infested with one or more aphids).

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Wheat stem maggot was observed in 16% of wheat fields surveyed in ND and the number of white heads ranged from one to 36% of plants infested. Wheat fields with high numbers of white heads, >20% incidence, were observed in Barnes, Cass, Ransom and Sargent Counties in southeast area (see map below).

 

Wheat stem sawfly was found in only 2% of the wheat fields surveyed in ND. In 2018, wheat stem sawflies were observed in northwest (Burke, Divide, McKenzie, Mountrail Counties); north central (Bottineau, McLean, Renville and Ward Counties) and southwest (Golden Valley County) areas of ND. The late summer drought impacted these sawfly-infested areas, increasing favorable conditions for wheat stem sawfly. Although populations were low statewide in 2018, wheat growers reported lodging problems from wheat stem sawfly in Bottineau, Renville and Ward Counties.

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Cereal leaf beetle is no longer a pest of export concern for shipments of hay from North Dakota to California or Canada; however, we still monitor cereal leaf beetle as an economic insect pest of wheat and barley. In 2018, there was only one observation of cereal leaf beetle in wheat in Divide County and no positive observations in barley. North Dakota counties that have had cereal leaf beetle detections in the past include Burke, Divide, McKenzie, Mountrail and Williams counties in northwest; Renville and Ward counties in north central; and Cavalier county in northeast.

Barley thrips were low and observed in only 14% of the barley fields surveyed from June through July. The central area of ND reported most of the barley thrips at an average of <1 thrips per stem, which is below the economic threshold. The rains in early summer helped reduce populations of barley thrips. The 2018 economic threshold for barley thrips was an average of >4 thrips per stem for malting barley.

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Diseases:

The two most common wheat diseases detected by IPM scouts in wheat were tan spot and bacterial leaf streak. Tan spot was recorded in 12.7% (Figure 1) of the fields and bacterial leaf streak was recorded in 10.4% (Figure 2) of the fields. Tan spot severity levels remained low and were not regularly detected on the flag leaf. However, in fields where bacterial leaf streak was found, extensive damage on the flag leaf was noticed likely leading to yield loss. Barley foliar diseases were found in 20% of the fields and were generally at very low severities. Bacterial leaf streak was the most common foliar disease detected (13%), followed by net blotch (11%), then spot blotch (8%).

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Fusarium head blight (scab) risk was moderate to high at various points in the growing season. The greatest areas of risk were in southwestern ND, central ND and northeastern ND. The NDSU IPM scouts visited 272 wheat fields during the time scab is most visible and documented the disease in 25% of the fields (Figure 3). Most fields were at low severity (< 5.0 severity index), while a few fields had moderate to high amounts of scab (> 10.0 severity index).

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Acknowledgments: Sincere thanks to the hard working field scouts of 2018! We also appreciate the help of Darla Bakko, NDSU Dept. of Plant Pathology, for data compilation, and Honggang Bu, NDSU Dept. of Soil Science, for ArcMap programming. This survey is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture and the North Dakota Department of Agriculture.

Janet J. Knodel 

Extension Entomology

 

Andrew Friskop

Extension Plant Pathology, Cereal Crops

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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