Harness® MAX Herbicide for Pre-emergence Weed Control

Trial Objective

• Harness® MAX is a pre-mix herbicide containing acetochlor (Harness® herbicide) plus mesotrione. Harness® MAX has a flexible application window including pre-plant, pre-emergence, and post-emergence up to 11-inch corn.
• There are multiple premixes available that contain different combinations of mesotrione with a group 15 herbicide, and these products have a range of use rates listed on the label.
• The objective of this study was to compare weed control and yield from Harness® MAX and competitor herbicides applied pre-emergence across a range of use rates.

Research Site Details

• The trial was arranged in a split-plot design with three replications.
• Herbicide treatments are listed in Table 1.
• Kochia was emerged at planting, so kochia control assessments reflect both the foliar efficacy of the treatments in addition to residual control of kochia that emerged after planting and herbicide application.
• Palmer amaranth and kochia pressure was extremely high (Figure 1).

Understanding the Results

• No crop injury was observed from any of the herbicide treatments.
• Numerical differences were observed in weed control between the different treatments for all species assessed, but significant differences were only observed for Palmer amaranth control (P = 0.06) (Figure 2).
• There were no significant differences in weed control between the herbicide treatments at the mid and high rates (Treatments 1-10).
• The addition of atrazine to Harness® MAX numerically improved weed control, and this treatment numerically provided the greatest level of control of all weed species compared to Harness® MAX alone, Acuron®, Resicore®, or Harness® Xtra.
• Harness® MAX provided statistically greater Palmer amaranth control and numerically greater kochia control compared to Resicore®.
• No significant differences in corn yield were observed (P = 0.14) (Figure 3).

What Does This Mean for Your Farm?

• Problematic weeds, such as Palmer amaranth and kochia, necessitate the use of pre-emergence and postemergence herbicides with both foliar and soil activity.
• At the lower end of use rates assessed, Harness® MAX plus atrazine provided the greatest control of Palmer amaranth, kochia, and green foxtail relative to competitive herbicide treatments.