Steve D. Ruhl, Agriculture and Natural Resources Extension Agent
Jeff Stachler, Horticulture and Crop Science Extension Associate
To evaluate the effect of several different herbicides on the control of annual grass and giant ragweed in corn.
| Cooperator: | Tom Weiler |
| County: | Morrow |
| Nearest town: | Chesterville |
| Drainage: | Systematically tiled |
| Soil type: | Sloan silty clay loam |
| Tillage: | Conventional |
| Previous Crop: | Soybeans |
| Hybrid: | Golden Harvest H-8877 |
| Soil Test: | pH = 7.0, P = 23 ppm,
K = 154 ppm |
| Fertilizer: | 200 lbs. of 19-19-19 at planting
110 lbs. of NH4 side-dressed on June 18 |
| Planting Date: | April 27, 2001 |
| Planting Rate: | 30,200 seeds/acre |
| Row Width: | 30-inch |
| Harvest Date: | October 22, 2001 |
| Herbicides: | See table |
The field chosen has moderate to high giant ragweed pressure and light annual grass (mostly giant foxtail) pressure. Thirteen different herbicide treatments and an untreated check were replicated four times in a randomized complete block design. Plot size was 10 feet wide by 40 feet in length. The preemergence herbicides were applied on May 1. The postemergence herbicides were applied on June 8 when the corn was 18 inches tall and fourth-collar stage; giant ragweed was 15 inches tall; and annual grasses were 3 to 5 inches tall. The treatments were applied with a backpack carbon-dioxide-pressurized sprayer with an output volume of 20 gallons per acre at 30 pounds of pressure per square inch. Weed control was evaluated, based upon a scale of 0% indicating no herbicide activity to 100% indicating complete plant death, on August 22, 2001.
| Table 1. Visual Evaluations of Control of Annual Grasses and Giant Ragweed in Corn a. | ||||||
| Weed Controld | ||||||
| Herbicide Treatmentb | Herbicide Rate | Treatment Timingc | Giant Ragweed | Annual Grass | Herbicide and Adjuvant Costse | Total Costf |
| % | $/A | $/A | ||||
| Define 60DF | 19.5 oz/A | PRE | 24.37 | |||
| Banvel 4 L | 8.0 oz/A | POST | 92 abc | 96a | 5.74 | 30.11 |
| Axiom 68DF | 21.5 oz/A | PRE | 21.70 | |||
| Banvel 4L | 8.0 oz/A | POST | 98 ab | 95a | 5.74 | 27.44 |
| Harness 7.0EC | 2.5 pt/A | PRE | 25.16 | |||
| Banvel 4L | 8.0 oz/A | POST | 100 a | 95 a | 5.74 | 30.90 |
| Dual II Magnum 7.64EC | 1.84 pt/A | PRE | 25.54 | |||
| Banvel 4L | 8.0 oz/A | POST | 84 bcd | 88 ab | 5.74 | 31.28 |
| Outlook 6.0EC | 19.5 oz/A | PRE | Price Unavailable |
Price Unavailable |
||
| Banvel 4L | 8.0 oz/A | POST | 84 bcd | 78 b | ||
| Degree 3.8EC | 4.6 pt/A | PRE | 25.21 | |||
| Banvel 4L | 8.0 oz/A | POST | 92 abc | 91 ab | 5.74 | 30.95 |
| Topnotch 3.2 EC | 2.75 qt/A | PRE | 24.66 | |||
| Banvel 4L | 8.0 oz/A | POST | 100 a | 95 a | 5.74 | 30.40 |
| Harness Xtra 5.6F | 2.65 qt/A | PRE | 89 abcd | 32 c | 24.16 | 24.16 |
| Dual II Magnum 7.64EC | 1.5 pt/A | PRE | 20.88 | |||
| Callisto 4SC + | 4.0 oz/A | POST | 13.33 | |||
| COC + | 1.0 %v/v | POST | 1.52 | |||
| UAN - 28% N | 2.5 %v/v | POST | 82 cd | 94 a | 0.58 | 36.31 |
| Dual II Magnum 7.64EC | 1.5 pt/A | PRE | 20.88 | |||
| Callisto 4SC + | 4.0 oz/A | POST | 13.33 | |||
| Atrazine 90DF + | 0.28 lb/A | POST | 0.65 | |||
| COC + | 1.0 %v/v | POST | 1.52 | |||
| UAN - 28% N | 2.5 %v/v | POST | 86 abcd | 88 ab | 0.58 | 36.96 |
| Leadoff 5.0L | 1.0 qt/A | PRE | 10.04 | |||
| Basis Gold 89.5DF + | 14 oz/A | POST | 18.53 | |||
| Distinct 76.4DF + | 1.0 oz/A | POST | 2.24 | |||
| MSO + | 0.5 %v/v | POST | 1.60 | |||
| UAN - 28% N | 1.25 %v/v | POST | 78 d | 91 ab | 0.29 | 32.70 |
| Epic 58DF | 12 oz/A | PRE | 22.80 | |||
| Aim 40DG + | 0.33 oz/A | POST | 2.76 | |||
| Atrazine 90DF + | 1.5 lb/A | POST | 3.50 | |||
| NIS + | 0.25 %v/v | POST | 0.80 | |||
| UAN - 28% N | 2.5 %v/v | POST | 100 a | 99 a | 0.58 | 30.44 |
| Princep 4F | 1.5 qt/A | PRE | 6.70 | |||
| Distinct 76.4DF + | 6.0 oz/A | POST | 13.44 | |||
| NIS + | 0.25 %v/v | POST | 0.80 | |||
| UAN - 28% N | 1.25 %v/v | POST | 81 cd | 95 a | 0.29 | 21.23 |
| LSD (0.05) | 14.3 | 14.4 | ||||
| F-Test | 2.5 | 12.0 | ||||
| CV | 11.1% | 11.5% | ||||
| a | Rainfall recorded in May was May 1 - 8 = 0.4 inch, May 9 - 15 = 1.2 inch, May 16 - 31 = 3.4 inch.
b |
All treatments were applied at 20 gallons per acre and 30 psi.
c |
PRE treatments were applied on May 1, 2001, and POST treatments were applied on June 8, 2001, with the corn being
18 inches tall and four collars (V-4), giant ragweed being 15 inches tall, and annual grasses being 3 to 5 inches tall.
d |
Treatment means followed by the same letter are not significantly different. Visual evaluation of weed control was
done on August 22, 2001.
e |
All herbicides and adjuvant costs listed in the table were 2001 in-season retail prices.
f |
The total cost includes the herbicides and adjuvants only listed in the previous column (no herbicide application charges were included). |
Axiom, Harness, and Topnotch followed by Banvel and Epic followed by Aim plus Atrazine provided 98% or better control of giant ragweed. Dual II Magnum followed by Callisto, Leadoff followed by Basis Gold plus Distinct, and Princep followed by Distinct (6.0 oz/A) showed significantly lower giant ragweed control compared to the other treatments. All treatments provided greater than 90% control of annual grasses, except Dual II Magnum followed by Banvel, Outlook followed by Banvel, Harness Xtra, and Dual II Magnum followed by Callisto + Atrazine. The Princep followed by Distinct was the least expensive herbicide treatment. Acknowledgment
We would like to thank Tom Weiler and Dave Ufferman for their assistance in this project. We would also like to thank Golden Harvest for the seed used for the project. Thanks to Geoffrey Trainer (OSU Crop Science graduate student) for evaluating the weed control.
For additional information, contact: Steve Ruhl, Ohio State University Extension, Morrow County, 871 W. Marion Rd., Suite 102, Mt. Gilead, OH 43338, 419-947-1070, ruhl1@postoffice.ag.ohio-state.edu