Table 2. Summary of Key Row Crop Weeds and Herbicide Efficacy.
| weed speciesa |
control rating (0−10) and resistance statusb,c |
|||||||
|---|---|---|---|---|---|---|---|---|
| common name | scientific name | glyphosate | glufosinate | ALS inhibitors | synthetic auxins | HPPD inhibitors | PPO inhibitors | ACCase inhibitors |
| Dicotyledons | ||||||||
| common lambsquarters | Chenopodium album L. | 8R | 8 | 7R | 9R | 9 | 9 | 0 |
| redroot pigweed | Amaranthus retroflexus L. | 9 | 8 | 9R | 9 | 9 | 9 | 0 |
| waterhemp | Amaranthus tuberculatus (Moq.) Sauer | 9R | 8 | 9R | 8 | 9 | 9R | 0 |
| Palmer amaranth | Amaranthus palmeri S. Wats. | 9R | 8 | 9R | 9 | 9 | 9 | 0 |
| velvetleaf | Abutilon theophrasti Medik. | 8 | 8 | 8−9 | 8 | 9 | 8 | 0 |
| common cocklebur | Xanthium strumarium L. | 9 | 9 | 9R | 9 | 8 | 8 | 0 |
| common ragweed | Ambrosia artemisiifolia L. | 8R | 9 | 8R | 9 | 7 | 9R | 0 |
| giant ragweed | Ambrosia trifida L. | 7−8R | 8 | 7−8R | 9 | 8 | 8 | 0 |
| horseweed | Conyza canadensis (L.) Cronq. | 7−8R | 8 | 7R | 8 | 8 | 8 | 0 |
| morningglories | Ipomoea spp. | 7 | 8 | 7 | 9 | 7 | 8 | 0 |
| kochia | Kochia scoparia (L.) Schrad. | 9R | 8 | 9R | 9R | 7 | 8 | 0 |
| common sunflower | Helianthus annuus L. | 9 | 9 | 9R | 9 | 9 | 8 | 0 |
| Monocotyledons | ||||||||
| giant foxtail | Setaria faberi Herrm. | 9 | 9 | 8R | 0 | 8 | 7 | 9R |
| green foxtail | Setaria viridis (L.) Beauv. | 10 | 8 | 9R | 0 | 4 | 5 | 9R |
| yellow foxtail | Setaria pumila (Poir.) Roemer & J.A. Schultes | 9 | 8 | 9R | 0 | 6 | 7 | 9 |
| johnsongrass (rhizome) | Sorghum halepense (L.) Pers. | 9R | 6 | 8R | 0 | 0 | 8 | 9R |
| shattercane | Sorghum bicolor (L.) Moench | 10 | 9 | 10R | 0 | 8 | 7 | 9Rd |
| large crabgrass | Digitaria sanguinalis (L.) Scop. | 9 | 8 | 9R | 0 | 7 | 6 | 9R |
| barnyardgrass | Echinochloa crus-galli (L.) Beauv. | 9 | 9 | 9R | 0 | 7 | 6 | 9R |
| woolly cupgrass | Eriochloa villosa (Thunb.) Kunth. | 9 | 9 | 9 | 0 | 7 | 5 | 8 |
| fall panicum | Panicum dichotomiflorum Michx. | 9 | 8 | 8 | 0 | 5 | 4 | 9R |
| Italian ryegrass | Lolium multiflorum L. | 9R | 8 | 8R | 0 | 3 | 3 | 9R |
| feral corn | Zea mays L. | 9R | 7R | 8R | 0 | 0 | 6 | 9Re |
a
Weed selection determined by a market research survey of U.S. corn, soybean, and cotton growers by Gfk Kynetec, Inc., St. Louis, MO (used with permission).
b
Weed control ratings are summarized from U.S. extension guides with 0 being the lowest and 10 being the highest level of control. A rating of ≥7 indicates effective herbicide control. Weed ratings represent the highest observed for any active in that class.
c
An R next to herbicide efficacy rating indicates that this weed has developed resistance to herbicide mode of action (Heap 2010).
d
ACCase resistance has been confirmed but not listed at Heap 2010.
e
ACCase trait currently under development and anticipated to be an issue in feral corn after commercialization.