North Dakota State University
NDSU Extension Service

Survey of Weeds in North Dakota - 2000

ER-83, May 2003
R. K. Zollinger, NDSU Extension Weed Specialist

Table 33. Griggs county weed infestations based on 19 surveyed fields, spring 2000.
        Weed  
  Weed Field Uniformity Weed Density Density Range Weed
Weed species Frequency All Infested All Infested Low High Index
  (%) (%) (%) - - Plants/m2 - - - - Plants/m2 - -  
Green foxtail 78.9 21.1 26.7 33.5 42.4 1.8 18.6 125.5
Yellow foxtail 73.7 38.9 52.9 21.5 29.1 0.2 11.3 113.6
Wild buckwheat 68.4 25.8 37.7 5.8 8.4 <0.1 3.2 62.1
Wild mustard 63.2 22.6 35.8 7.9 12.5 0.1 4.3 62.1
Pigweed species 47.4 16.3 34.4 11.7 24.8 0.2 8.8 59.5
Canada thistle 78.9 22.1 28.0 4.4 5.5 <0.1 2.4 58.6
Volunteer cereal 42.1 20.0 47.5 5.1 12.1 <0.1 3.4 45.9
Kochia 36.8 14.7 40.0 6.4 17.4 <0.1 7.4 42.0
Wild oat 47.4 14.2 30.0 3.4 7.2 <0.1 2.8 37.9
Common lambsquarters 36.8 5.8 15.7 0.8 2.3 <0.1 1.4 20.1
Quackgrass 26.3 4.7 18.0 1.0 3.9 <0.1 2.6 15.9
Nightflowering catchfly 15.8 5.8 36.7 1.6 10.4 <0.1 4.0 14.9
Annual smartweed 10.5 2.6 25.0 1.1 10.8 <0.1 8.0 8.8
Common milkweed 15.8 2.6 16.7 0.3 1.8 <0.1 1.0 8.6
Flax 5.3 3.2 60.0 1.5 28.0 <0.1 12.0 8.3
Perennial sowthistle 10.5 2.6 25.0 0.7 7.0 <0.1 3.5 7.9
Prostrate pigweed 5.3 2.6 50.0 1.2 23.7 <0.1 10.0 7.3
Giant ragweed 10.5 2.6 25.0 0.3 2.7 <0.1 1.0 6.8
Sunflower 5.3 3.2 60.0 0.5 9.7 <0.1 2.0 6.1
Alfalfa 5.3 2.6 50.0 0.5 9.7 <0.1 3.0 5.6
Soybean 5.3 2.6 50.0 0.5 9.7 <0.1 4.0 5.6
Dandelion 5.3 2.6 50.0 0.3 6.5 <0.1 2.0 5.2
Canola 5.3 2.1 40.0 0.2 4.3 <0.1 1.0 4.4
Russian thistle 5.3 0.5 10.0 0.1 2.2 <0.1 2.0 2.5
Common ragweed 5.3 0.5 10.0 0.1 1.1 <0.1 1.0 2.4
Common cocklebur 5.3 0.5 10.0 0.1 1.1 <0.1 1.0 2.4
Prairie wild rose 5.3 0.5 10.0 0.1 1.1 <0.1 1.0 2.4
Marshelder 5.3 0.5 10.0 0.1 1.1 <0.1 1.0 2.4
Greenflower pepperweed 5.3 0.5 10.0 0.1 1.1 <0.1 1.0 2.4
Weed free 21.1 3.2 15.0 - - - - -

Table 34. Hettinger county weed infestations based on 32 surveyed fields, spring 2000.
        Weed  
  Weed Field Uniformity Weed Density Density Range Weed
Weed species Frequency All Infested All Infested Low High Index
  (%) (%) (%) - - Plants/m2 - - - - Plants/m2 - -  
Green foxtail 87.5 38.4 43.9 20.2 23.1 0.2 9.2 114.8
Wild oat 65.6 23.4 35.7 7.5 11.4 <0.1 4.2 62.7
Kochia 43.8 18.8 42.9 9.6 21.8 0.1 17.9 55.6
Russian thistle 34.4 15.0 43.6 4.2 12.2 <0.1 4.4 36.3
Wild buckwheat 43.8 13.8 31.4 3.1 7.2 <0.1 2.6 35.6
Volunteer cereal 28.1 12.5 44.4 4.0 14.2 <0.1 6.0 31.2
Pigweed species 31.3 10.9 35.0 2.6 8.4 <0.1 3.2 27.5
Field bindweed 31.3 7.5 24.0 1.5 4.7 <0.1 2.1 21.4
Prickly lettuce 28.1 8.1 28.9 1.0 3.7 <0.1 1.6 19.9
Field pennycress 25.0 6.6 26.3 1.4 5.8 <0.1 2.9 18.3
Common lambsquarters 21.9 7.5 34.3 1.3 6.0 <0.1 2.4 17.9
Canola 12.5 5.6 45.0 2.7 21.8 <0.1 6.8 16.1
Wild mustard 21.9 5.9 27.1 0.8 3.5 <0.1 1.6 15.0
Flixweed/Tansy mustard 18.8 5.0 26.7 0.8 4.3 <0.1 2.2 13.1
Dandelion 15.6 4.7 30.0 0.7 4.3 <0.1 1.8 11.5
Sunflower 9.4 3.8 40.0 1.7 18.7 <0.1 6.0 11.0
Curly dock 15.6 2.5 16.0 0.4 2.4 <0.1 1.6 8.6
Prairie wild rose 9.4 2.2 23.3 0.4 4.7 <0.1 2.7 6.3
Common ragweed 6.3 1.6 25.0 0.3 4.8 <0.1 2.5 4.4
Quackgrass 6.3 1.3 20.0 0.3 4.8 <0.1 3.5 4.0
Barnyardgrass 6.3 0.6 10.0 0.1 1.6 <0.1 1.5 2.9
Perennial sowthistle 3.1 0.9 30.0 0.1 4.3 <0.1 2.0 2.3
Canada thistle 3.1 0.6 20.0 0.1 3.2 <0.1 2.0 1.9
Common milkweed 3.1 0.6 20.0 0.1 2.2 <0.1 1.0 1.8
Common mallow 3.1 0.6 20.0 0.1 2.2 <0.1 1.0 1.8
Field sandbur 3.1 0.6 20.0 0.1 2.2 <0.1 1.0 1.8
Downy brome 3.1 0.3 10.0 0.1 3.2 <0.1 3.0 1.6
Yellow foxtail 3.1 0.3 10.0 0.1 2.2 <0.1 2.0 1.5
Wild-proso millet 3.1 0.3 10.0 0.1 2.2 <0.1 2.0 1.5
Annual smartweed 3.1 0.3 10.0 <0.1 1.1 <0.1 1.0 1.4
Weed free 6.3 1.3 20.0 - - - - -

Table 35. Kidder county weed infestations based on 10 surveyed fields, spring 2000.
        Weed  
  Weed Field Uniformity Weed Density Density Range Weed
Weed species Frequency All Infested All Infested Low High Index
  (%) (%) (%) - - Plants/m2 - - - - Plants/m2 - -  
Green foxtail 100.0 37.0 37.0 49.4 49.4 3.8 43.7 185.6
Wild buckwheat 80.0 42.0 52.5 39.1 48.8 1.5 18.3 159.8
Wild mustard 70.0 25.0 35.7 11.5 16.5 0.2 9.6 75.2
Common lambsquarters 80.0 20.0 25.0 11.9 14.9 0.1 4.9 74.5
Quackgrass 60.0 18.0 30.0 11.4 19.0 <0.1 9.7 64.6
Pigweed species 40.0 14.0 35.0 5.3 13.2 <0.1 6.0 39.6
Wild oat 40.0 11.0 27.5 3.6 8.9 <0.1 3.8 32.6
Field bindweed 40.0 10.0 25.0 1.1 2.7 <0.1 1.0 25.8
Shepherd's-purse 20.0 7.0 35.0 5.1 25.3 <0.1 9.5 25.5
Leafy spurge 10.0 9.0 90.0 5.3 52.7 0.1 13.0 24.6
Canada thistle 30.0 4.0 13.3 1.2 3.9 <0.1 3.3 16.8
Field pennycress 20.0 4.0 20.0 0.8 3.8 <0.1 2.0 12.4
Perennial sowthistle 10.0 3.0 30.0 2.3 22.6 <0.1 18.0 11.6
Sunflower 10.0 4.0 40.0 1.2 11.8 <0.1 6.0 10.1
Alfalfa 20.0 2.0 10.0 0.3 1.6 <0.1 1.5 9.4
Foxtail barley 20.0 2.0 10.0 0.2 1.1 <0.1 1.0 9.2
Common milkweed 10.0 1.0 10.0 0.5 5.4 <0.1 5.0 5.6
Prickly lettuce 10.0 1.0 10.0 0.3 3.2 <0.1 3.0 5.1
Yellow foxtail 10.0 1.0 10.0 0.1 1.1 <0.1 1.0 4.6
Sweetclover 10.0 1.0 10.0 0.1 1.1 <0.1 1.0 4.6
Weed free 10.0 2.0 20.0 - - - - -

Table 36. LaMoure county weed infestations based on 38 surveyed fields, spring 2000.
        Weed  
  Weed Field Uniformity Weed Density Density Range Weed
Weed species Frequency All Infested All Infested Low High Index
  (%) (%) (%) - - Plants/m2 - - - - Plants/m2 - -  
Green foxtail 57.9 15.5 26.8 15.7 27.2 3.8 21.3 71.6
Wild mustard 52.6 18.7 35.5 10.0 18.9 0.1 11.9 59.5
Pigweed species 44.7 17.1 38.2 4.8 10.8 <0.1 3.5 43.3
Sunflower 34.2 13.7 40.0 6.8 19.9 0.1 6.0 41.0
Yellow foxtail 21.1 8.9 42.5 9.5 45.2 0.7 32.6 38.2
Canada thistle 50.0 13.7 27.4 2.7 5.4 <0.1 2.3 36.7
Wild oat 23.7 7.4 31.1 4.3 18.1 0.1 8.3 25.2
Common lambsquarters 21.1 7.6 36.3 3.0 14.3 <0.1 5.4 21.7
Kochia 13.2 5.0 38.0 4.3 32.7 0.1 10.4 19.4
Wild buckwheat 21.1 7.6 36.3 1.6 7.5 <0.1 3.1 18.4
Quackgrass 26.3 3.4 13.0 1.1 4.1 <0.1 3.3 14.7
Eastern black nightshade 18.4 3.9 21.4 0.8 4.6 <0.1 1.9 12.1
Soybean 13.2 3.4 26.0 0.5 3.9 <0.1 2.0 9.0
Common milkweed 13.2 2.4 18.0 0.4 2.8 <0.1 1.6 7.6
Flax 2.6 2.4 90.0 1.8 66.7 <0.1 33.0 7.3
Volunteer cereal 13.2 2.1 16.0 0.3 2.4 <0.1 1.6 7.2
Common ragweed 13.2 1.8 14.0 0.3 2.4 <0.1 1.2 7.0
Perennial sowthistle 10.5 1.6 15.0 0.2 2.2 <0.1 1.5 5.6
Field pennycress 7.9 1.6 20.0 0.3 3.2 <0.1 1.7 4.8
Field bindweed 7.9 1.3 16.7 0.2 2.5 <0.1 1.7 4.4
Prickly lettuce 7.9 1.1 13.3 0.1 1.4 <0.1 1.0 3.9
Russian thistle 5.3 0.5 10.0 0.2 3.8 <0.1 3.5 2.7
Common cocklebur 5.3 0.8 15.0 0.1 1.6 <0.1 1.0 2.7
Barnyardgrass 2.6 0.5 20.0 0.5 17.2 <0.1 11.0 2.5
Horseweed 2.6 0.5 20.0 0.1 3.2 <0.1 2.0 1.6
Curly dock 2.6 0.3 10.0 <0.1 1.1 <0.1 1.0 1.2
Dandelion 2.6 0.3 10.0 <0.1 1.1 <0.1 1.0 1.2
Prairie wild rose 2.6 0.3 10.0 <0.1 1.1 <0.1 1.0 1.2
Weed free 52.6 17.1 32.5 - - - - -

Table 37. Logan county weed infestations based on 11 surveyed fields, spring 2000.
        Weed  
  Weed Field Uniformity Weed Density Density Range Weed
Weed species Frequency All Infested All Infested Low High Index
  (%) (%) (%) - - Plants/m2 - - - - Plants/m2 - -  
Green foxtail 90.9 54.5 60.0 23.1 25.4 <0.1 21.3 138.7
Wild buckwheat 72.7 29.1 40.0 13.7 18.8 <0.1 9.8 85.3
Wild oat 45.5 17.3 38.0 20.8 45.9 0.6 19.4 81.1
Wild mustard 36.4 20.0 55.0 11.8 32.6 <0.1 11.5 59.7
Sunflower 36.4 19.1 52.5 4.9 13.5 <0.1 4.3 42.6
Field bindweed 45.5 10.0 22.0 2.5 5.6 <0.1 3.4 31.1
Common lambsquarters 27.3 9.1 33.3 5.0 18.3 <0.1 5.7 29.8
Kochia 18.2 4.5 25.0 8.1 44.7 <0.1 50.0 29.6
Pigweed species 27.3 8.2 30.0 1.4 5.0 <0.1 2.3 20.5
Quackgrass 36.4 3.6 10.0 1.5 4.0 <0.1 3.8 19.2
Canola 9.1 <0.1 <0.1 6.8 74.3 0.2 20.0 18.8
Russian thistle 27.3 2.7 10.0 0.3 1.1 <0.1 1.0 12.5
Canada thistle 18.2 3.6 20.0 0.8 4.3 <0.1 2.0