OBJECTIVE: To determine the efficacy of Barricade preemergence herbicide applied at
nontraditional times in a perennial ryegrass turf.
PERSONNEL: Ward Upham and Jack Fry
SPONSOR: Sandoz
MATERIALS AND METHODS:
A perennial ryegrass turf, located at the KSU Rocky Ford Turfgrass Research Center near Manhattan, KS, was used for this study. Herbicides, treatment dates, and application rates are given in Table 1.
Treatments were applied with a backpack CO2 sprayer equipped with 8004 flat-fan nozzles and calibrated to deliver 60 GPA (1.4 gal/1000 ft2) at 35 psi. Plot size was 1 x 2 meters, and the experimental design was a randomized complete block with three replications.
Plots were examined for crabgrass starting in May of 1995, but it did not begin to invade until August. Plots were rated on 8/9 and 8/18 by a visual estimation of the percent of plot covered with crabgrass. Percent control was determined by normalizing each treatment to the untreated plot of that replication. The following equation was used:
Ninety percent control was considered "good".
Data were subjected to analysis of variance, and means were separated using the Waller
Duncan Bayesian k ratio t test (k = 100, P = 0.05).
RESULTS:
Barricade was the only preemergence herbicide that provided season-long control and then only if used at the higher rates. The 0.49 lb rate of Barricade did not provide adequate control for the October 14, November 1, or March 14 application dates but did for the April 14 date. Barricade applied at the 0.65 and 0.75 lb rates during the fall of 1994 gave good control through 1995, except for the 0.75 rate applied on October 14.
Pre-M has a relatively short period of activity and failed at the 1.5 lb rate even when applied in April. Normally, if a single application of Pre-M is used, it is at the 3 lb rate.
Dimension did not show consistently good control through August, regardless of application date. However, it was applied at 0.38 lbs ai/a rather than the more traditional 0.5.
| Table 1. Percent crabgrass control with Barricade applied at nontraditional times at Manhattan, KS - 1995. | ||||||||
| Treatment | Rate (lbs ai/a) | Date of Application | Crabgrass | |||||
| % of Plot Covered* | % Control** | |||||||
| Aug. 9 | Aug. 18 | Aug. 9 | Aug. 18 | |||||
| Check | ---- | ---- | 23.3 | 30.0 | 0.0 | 0.0 | ||
| Barricade | 0.49 | October 14 | 6.7 | 18.3 | 73.3 | 46.7 | ||
| Barricade | 0.65 | October 14 | 1.0 | 1.0 | 96.0 | 96.0 | ||
| Barricade | 0.75 | October 14 | 2.0 | 2.7 | 91.0 | 89.3 | ||
| Pre-M | 1.5 | October 14 | 10.0 | 13.3 | 56.7 | 46.7 | ||
| Dimension | 0.38 | October 14 | 7.7 | 6.7 | 67.7 | 73.3 | ||
| Barricade | 0.49 | November 1 | 16.7 | 30.0 | 23.3 | -12.5 | ||
| Barricade | 0.65 | November 1 | 0.0 | 1.3 | 100.0 | 94.7 | ||
| Barricade | 0.75 | November 1 | 0.0 | 1.0 | 100.0 | 97.5 | ||
| Barricade | 0.49 | March 14 | 2.0 | 4.3 | 91.0 | 85.2 | ||
| Barricade | 0.65 | March 14 | 1.0 | 0.0 | 96.0 | 100.0 | ||
| Pre-M | 1.5 | March 14 | 3.7 | 5.0 | 84.3 | 82.5 | ||
| Dimension | 0.38 | March 14 | 2.7 | 2.3 | 87.7 | 90.7 | ||
| Barricade | 0.49 | April 14 | 2.0 | 2.0 | 91.0 | 92.0 | ||
| Barricade | 0.65 | April 14 | 2.0 | 2.3 | 92.0 | 92.2 | ||
| Pre-M | 1.5 | April 14 | 11.0 | 9.3 | 51.0 | 72.7 | ||
| Dimension | 0.38 | April 14 | 1.7 | 3.3 | 93.3 | 86.7 | ||
| MSD*** | 9.7 | 15.3 | 43.3 | 50.8 | ||||
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