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2019 ND IPM Survey Results in Small Grains (09/12/19)

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.

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. Nine 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:

  • Allison Fugle, central and south central counties, worked out of Carrington REC with Greg Endres
  • Kia Ward, southwest and west central counties, worked out of Dickinson REC with Ryan Buetow
  • Caleb Cross and Riley Racine, north central counties, worked out of NCREC in Minot with Travis Prochaska
  • Scott Roseth and Nicole Stanhope, northwest counties, worked out of Williston REC with Audrey Kalil
  • Tyler Lux, southeast and east central counties, worked out of NDSU campus, Fargo with Jan Knodel, Andrew Friskop and Sam Markell.
  • Nancy Feil 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 902 wheat fields (winter wheat, hard red spring wheat, durum wheat) and 103 barley fields for 18 diseases and 6 insect pests in North Dakota in 2019.  The survey was initiated on June 3rd and continued through August 16th. Crops were surveyed from the 2-leaf stage (seedling) 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 2019 IPM Survey in North Dakota were uploaded weekly onto the NDSU IPM website. Some of the pest highlights for wheat and barley are summarized below.

 

Grasshoppers – Grasshoppers were surveyed for in all crops, including wheat, barley, soybeans and sunflowers. Adult grasshoppers were observed in 86% of the fields surveyed. This was an increase in the incidence of adult grasshoppers from last year’s 75% in 2018 and only 36% in 2017. The number of adult grasshoppers per 4 sweeps (1 yd2) ranged from 0 to 35 per 4 sweeps. The highest infestations were most common in the dryer areas in the northeastern and north central areas of ND. The cool spring and late crop planting favored grasshopper development and reproduction since grasshopper emergence was delayed and by the time grasshoppers emerged, there were ample crops to feed on. The wet conditions in some areas of ND did not seem to negatively impact grasshopper infestations. Feeding injury was present on field edges in most fields. However, some fields needed a whole-field treatment. Grasshopper ‘Hot spots’ in 2019 included Benson, Pembina, Ramsey, Sheridan, Towner, Walsh, Ward Counties.

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Insect Pests of Small Grains:

Grain aphid numbers were very low and observed in only 16% of the wheat fields and 15% of the barley fields surveyed in North Dakota. Grain aphids were first detected late in the year (June 27) and populations never developed into damaging levels (85% of stems infested with one or more aphids). In wheat, the percentage of infested stems ranged from 1-40% with an average of 7%. In barley, the percentage of infested stems ranged from 2-36% with an average of 10%. Higher infestations were observed in late July into August when the wheat and barley were not susceptible to yield losses.

 

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Wheat stem maggot was observed in 17% of wheat fields surveyed in ND and damaged ranged from 1-56% of plants with damaged heads (white heads). Wheat fields with >20% damaged heads were observed in northwest (Burke, Divide, McKenzie Counties), north central (Mountrail County) and northeast (Cavalier and Walsh Counties).

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Wheat stem sawfly was collected with sweep nets in only 5% of the wheat fields surveyed during late July through mid-August in 2019. However, wheat stem sawflies were more common and widespread than in 2018. Wheat stem sawflies were observed in the northwest (Burke, Divide, Mountrail and Williams Counties); north central (McLean, Renville, Sheridan and Ward Counties) and southwest (Billings, Dunn, Golden Valley, Grant, Hettinger, Morton, Oliver, Slope and Stark Counties) areas of North Dakota. The summer drought in the northern areas of North Dakota favored development and reproduction of wheat stem sawfly. Although populations were low statewide in 2019, 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 2019, there was only one observation of cereal leaf beetle in wheat, in Nelson County. This is a new county record for cereal leaf beetle in ND. No positive observations of cereal leaf beetle were detected in barley. The updated counties of North Dakota that are infested with cereal leaf beetle include:  Burke, Divide, McKenzie, Mountrail and Williams counties in northwest; Renville, McHenry and Ward counties in north central; and Cavalier and Nelson counties in northeast.

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Barley thrip numbers were low and observed in only 10% of the barley fields surveyed from late June through mid-July. The central area of ND reported most of the barley thrips at an average of <1 thrips per stem, which is not economic for barley. The 2019 economic threshold for barley thrips was an average of >4 thrips per stem for malting barley and 6-8 thrips per stem for feed barley.

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Foliar Diseases of Small Grains:  

 

Tan spot and bacterial leaf streak were the two most prevalent foliar diseases in wheat in 2019. Tan spot was recorded in 27.5% % of the fields (Figure 1), which is up 12.7% from 2018. A big reason why tan spot was detected more frequently in 2019 could be attributed to weather conditions (cool and wet in late May and early June). Another disease that was noted regularly was bacterial leaf streak and was identified in 13.6% of the fields (Figure 2). Severity (area covered by disease lesions) for both tan spot and bacterial leaf streak varied, and high levels of both diseases were detected in several fields. Fungal leaf spots (net blotch and spot blotch) were the most common diseases in barley and were collectively identified in 29% of the fields.

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Fusarium head blight (scab) risk was moderate to high for several areas of the state this growing season. Areas under the greatest risk included southeast ND and southwest ND. The NDSU IPM scouts visited 284 wheat fields after the flowering stages of wheat and documented scab in 27% 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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Janet J. Knodel                                                                                                  Andrew Friskop

Extension Entomologist                                                                                 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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