Herbicide Selection Results for Foxtail Before or After Emergence in Turfgrass Areas

This study was conducted at the University of Nebraska’s East Campus Turf Research Center at Lincoln, NE, on a 7-year-old stand of Kentucky bluegrass mismanaged with low fertility and low mowing to encourage yellow foxtail growth.  Populations of foxtail ranged from 12-40% over the course of the trial in untreated plots. The stand was mowed at 2 inches and irrigated to prevent drought stress. Plots were 5' x 5' and sprayed with a CO₂ backpack sprayer using a 3-nozzle boom with 8002 vs nozzles at 30 psi. Treatments were initiated on May 5th with separate timings with or without a sequential application starting on June 27th at 3-5 leaf foxtail and or July 15th at 3 tiller foxtail. At no time during evaluations did any of these products result in damage to the Kentucky bluegrass stand. 

Yellow Foxtail Results 

Yellow foxtail can be a difficult weed to control with postemergence herbicides. This trial was designed to help determine the timings of the herbicide application that works the best. Applications were made on A=May 1 for pre-emergence control, B= June 27 for 3 to 5 leaf foxtail, or C= July 15 for 3-tiller foxtail. Ratings were taken on June 25, July 7, July 15, July 28, and August 15, 2025. The percentage of cover of yellow foxtail is listed in Table 1a. 

Preliminary data results on Table 1b, indicate that the high label rates of the 3 most commonly used preemergent herbicides and a newer granular called Crew applied on May 8^th provide near 100% control to that point in the year.  Post treatments that were applied at the 3-5 leaf stage of yellow foxtail resulted in variable control depending on the herbicide applied. Acclaim Extra at both the 14 and 28 oz rate resulted in the highest control at near 100% with Drive XLR8, Tenacity, Pylex, Q4 Plus, and Solitare, resulting in lower control at the July 15^th rating, ranging from 60-75%.

Key Takeaways at the end of the study: 

1. Preemergent applications at the high label rate applied on May 1 resulted in 88-97% control of Foxtail up to the August 15th rating.
2. One product killed foxtail at the 3-5 leaf stage, and it was a single application of Acclaim Extra at rates of 14 or 28 floz/A, resulting in 83-92% control similar to that of the pre applications by August 15th.
3. Tenacity applied in sequential apps or Acclaim Extra at both rates applied in a single app at the 3 tiller stage of foxtail resulted in roughly 50% control of foxtail, whereas the rest of the products remained at less than 26% control.

Prostrate Spurge Control? 

During this study, there was also a control for prostrate spurge in the same research plots. Table 2 shows the percentage of cover and control of prostrate spurge. Q4 Plus showed the effective control of prostrate spurge at 93%. Crew and Roundup for Lawns also show effective control at 82% and 80%, respectively.