Table 2.2-6. Relative effectiveness of "burndown" treatments for no-till corn.

This table compares the relative effectiveness of herbicides on individual weeds. Ratings are based on labeled application rates and weed size or growth stage. Treatments are rated only for control of vegetation existing at the time of application. Add preemergence herbicides (Table 2.2-10) as required for the specific situation.
Weed control rating:
10 = 95-100% 9 = 85-95% 8 = 75-85% 7 = 65-75%
6 = 55-65% N = less than 55%
or no control		     — = not applicable  
Herbicide¹ Alfalfa
sod		 Brome-
grass or
quack-
grass sod		 Burdock Canada
thistle		 Chick-
weed		 Common4
groundsel		 Common
ragweed		 Dan-
delion		 Downy
brome		 Field
violet/
pansy		 Annual
Flea-
banes
2,4-D (spring-applied) 1 pt 7+ N 7 8 6 6 9 8 N 6 6
2,4-D + Clarity (spring-applied) 9 N 8 8+ 8 7 9 8 N 7 8
Atrazine 6 8 6 6 8 9 9 9 7 8 7+
Atrazine + 2,4-D 8 7 7+ 8+ 8 9 9 9 7 8 7+
Autumn + 2,4-D (fall-applied) 7 N 9 6 9 8 — 9 N 6 8
Glyphosate (fall applied)² 8+ 9 8+ 9 9 9 — 9 9 7 8
Glyphosate (spring applied)² 7 9 7 8 9 9 9 6 9 6 7+
Glyphosate + 2,4-D or Clarity (fall applied_ 9+ 9 9+ 9+ 9 9 — 9 9 7 95
Glyphosate + 2,4-D or Clarity (spring applied) 8+ 9 7+ 8+ 9 9 9 8 9 8 8
Glyphosate + Atrazine 7+ 9 7+ 8 9 9 9 7 9 8 7+
Glyphosate + Sencor 7 9 7 8 9 9 9 6 9 8 8
Gramoxone N 6 N 6 8+ 8+ 8 N 7 8 6
Gramoxone + 2,4-D or Clarity² 7+ 6 7 8 9 8+ 9 7 7 8+ 7
Gramoxone + Atrazine 7 8 6 7 9 8+ 9 N 8 8 7
Gramoxone + Sencor N 6 6 6 9 8+ 9 N 7 8 6
Harmony Extra 6 N 6 8 9 9 6 6 N N N
Hornet (spring applied) 8 N 8 8 N 8+ 9 6 N N 9
Valor N N N N 9 7 7 86 N N N
Table 2.2-6. Relative effectiveness of “burndown” treatments for no-till corn. (Cont.)
Herbicide¹ Foxtail Hairy
vetch		 Hemp
Dogbane,
Dewberry,
Milkweed, etc.		 Henbit/
dead-
nettle		 Horseweed/
Marestail³		 Lambs-
quarters		 TR
Lambs-
quarters
2,4-D (spring-applied) 1 pt N 9 N N 8+ 9 9
2,4-D + Clarity (spring-applied) N 9+ 6 6 9 9 9
Atrazine 7 7 N 8 8 9 N
Atrazine + 2,4-D 7 9 N 8 9 9 9
Autumn + 2,4-D (fall-applied) N 9 N 9 9 — —
Glyphosate (fall applied)² — 8 8+ 8 8+5 — —
Glyphosate (spring applied)² 9 8 N 9 9 9 9
Glyphosate + 2,4-D or Clarity (fall applied_ — 9 9 8+5 9+5 7 —
Glyphosate + 2,4-D or Clarity (spring applied) 9+ 9 7+ 8+ 9 9 9
Glyphosate + Atrazine 9 8 N 9 9 9 9
Glyphosate + Sencor 9 7 7 8+ 8+ 9 9
Gramoxone 9 7 6 7 7 8 8
Gramoxone + 2,4-D or Clarity² 9 9 6 8 8+ 9 9
Gramoxone + Atrazine 9 8 6 9 8+ 9 8
Gramoxone + Sencor 9 7 6 8 8 9 8
Harmony Extra N 8 6 8 7+ 9 9
Hornet (spring applied) N 9 N N 8+ — 7
Valor N N N 7 6 9 9
Table 2.2-6. Relative effectiveness of "burndown" treatments for no-till corn. (Cont.)
Herbicide¹ Mustards
spp.		 Orchard-
grass or
fescue
sod		 Red
clover		 Rye cover,
volunteer
small
grains		 Smartweed Timothy,
blue-
grass
2,4-D (spring-applied) 1 pt 9 N 9 N 7 N
2,4-D + Clarity (spring-applied) 9 N 9+ N 9 N
Atrazine 8 6 6 6 9 6
Atrazine + 2,4-D 9 6 9 6 9 6
Autumn + 2,4-D (fall-applied) 9 N 9 N — N
Glyphosate (fall applied)² 9 9 8+ 9+ — 9+
Glyphosate (spring applied)² 9 7 7 9+ 7 9+
Glyphosate + 2,4-D or Clarity (fall applied_ 95 9 9 9 — 9+
Glyphosate + 2,4-D or Clarity (spring applied) 9 7 9 9+ 8+ 9+
Glyphosate + Atrazine 9 7+ 7+ 9 9 9
Glyphosate + Sencor 9 7 7 9 9 9
Gramoxone 8 N 8 8 7 7
Gramoxone + 2,4-D or Clarity² 9 N 9 8 8+ 7
Gramoxone + Atrazine 8+ 7 8 9 9 9
Gramoxone + Sencor 8+ N 8 8+ 9 7
Harmony Extra 9 N 7 N 9 N
Hornet (spring applied) N N 8 N 7 N
Valor 8 N N N 7 N
  1. See Table 2.2-1 for additional formulations or trade names containing some of these same active ingredients.
  2. Activity is reduced if applied in certain tank-mixes; Roundup or Touchdown with photosynthesis inhibitors such as triazine herbicides; 2,4-D and Clarity with Gramoxone. May still be tank-mixed for convenience, but burndown is improved if applied separately.
  3. Roundup, Touchdown, and other glyphosate products are not effective on glyphosate-resistant horseweed biotypes.
  4. Certain populations of common groundsel in the northeastern US are resistant to triazine herbicides. Herbicide programs that contain bromoxynil (Buctril) or clopyralid (Stinger) provide good control of groundsel in-crop.
  5. Based on control in early spring. Emergence of seedlings in the spring will reduce effectiveness.
  6. Valor provides control of germinating dandelion seedling; however, it is weak on dandelion when applied post.