Influence of Cultural Practices on Torpedograss Competition with Two Warm-Season Lawn Grasses

Torpedograss is becoming an increasing weed problem in centipedegrass and St. Augustinegrass home lawns due to sod or soil contamination. Currently, the use of non-selective herbicides and/or renovation is the primary means of torpedograss control. Minimal research has examined cultural methods for torpedograss control; therefore, a study was conducted evaluating nitrogen (N) and mowing heights for the control of torpedograss in centipedegrass and St. Augustinegrass. St. Augustinegrass was fertilized at 0 kg N/ha/month, 50 kg N/ha/month, or 100 kg N/ha/month and maintained at heights of 5.0 cm, 7.6 cm, or 10.2 cm. Centipedegrass was fertilized at 0 kg N/ha/month, 12.5 kg N/ha/month, or 25 kg N/ha/month and mowed at 2.5 cm, 5.0 cm, or 7.6 cm. The highest mowing height resulted in the greatest torpedograss encroachment with each species when compared to the low and recommended heights. Nitrogen fertility had no effect on torpedograss encroachment in either species. All mowing height and N combinations exhibited patterns of increasing torpedograss encroachment over time. These data indicate the use of uncontaminated soils or applications of non-selective herbicides represent the best methods for controlling torpedograss in St. Augustinegrass and centipedegrass.