Skip to main content
ARS Home » Research » Publications at this Location » Publication #111348
Title: WEED CONTROL IN FIELD CORN WITH RPA 201772 COMBINATIONS WITH ATRAZINE AND S-METOLACHLOR

Author
item TAYLOR-LOVELL, SARAH - UNIV OF ILLINOIS
item WAX, LOYD

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/8/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: We conducted research to learn the minimum rate of a new herbicide, isoxaflutole, that would be needed to provide consistent control of broadleaf weeds in corn, when used in combination with other herbicides. A wide range of isoxaflutole rates were tank-mixed with S-metolachlor/atrazine with special emphasis on finding the lowest rates that would provide velvetleaf control, while maintaining high corn yield. Each treatment was used as either early preplant (EPP), preemergence(PRE), or preplant incorporated (PPI). Isoxaflutole provided little control of the grass weed, giant foxtail. However, rates as low as 26 grams active ingredient per hectare of isoxaflutole increased broadleaf weed control and effectiveness generally improved with increasing rates. Compared with EPP applications, PPI and PRE applications generally provided the most effective weed control. These studies show that a very low dosage of the new herbicide isoxaflutole, when used with a standard soil-applied treatment, can significantly improve control of some broadleaf weeds, and is especially effective on velvetleaf. These findings should be beneficial to those scientists who are developing effective and economical weed management systems and providing guidelines to growers, dealers and consultants.

Technical Abstract: A wide range of isoxaflutole rates were tank-mixed with 3228 g ai/ha S-metolachlor/atrazine to compare velvetleaf density, weed control, corn injury, and corn yield. Rates of isoxaflutole included 0, 26, 53, 78, 105, and 132 g ai/ha to determine the minimum rate required to achieve adequate weed control. Each herbicide treatment was applied at three different timings: early preplant (EPP), preplant incorporated (PPI), and preemergence (PRE). Compared to atrazine/metolachlor alone, isoxaflutole provided little improvement on giant foxtail control. However, rates as low as 26 g ai/ha isoxaflutole significantly increased broadleaf weed control, and efficacy generally improved with increasing isoxaflutole rate. Control of large-seeded broadleaf weeds was 7% and 15% greater with the addition of 26 and 78 g ai/ha isoxaflutole, respectively. Although isoxaflutole improved efficacy on small-seeded broadleaves, S-metolachlor/atrazine alone provided acceptable control (90%) in most environments. Velvetleaf densities decreased with he addition of isoxaflutole at rates as low as 26 g ai/ha in combination with S-metolachlor/atrazine, compared to the latter alone, particularly in EPP applications. Preemergence and PPI applications provided superior weed control, lower velvetleaf densities, and greater corn yield compared with EPP applications when all herbicide treatments were combined. Weed control generally was greater with PRE than either PPI or EPP applications, except where precipitation was limited early in the season.