Bermudagrass Control in Tall Fescue with Turflon and Acclaim

Clint Waltz and Ted Whitwell

Department of Horticulture, Clemson University

Introduction and Objectives

Common bermudagrass (Cynodon dactylon) is a perennial weed of cool season turf in the transition zone. Acclaim is labeled for tall fescue (Festuca aurences), and can control invading bermudagrass with repeat applications. White clover (Trifolium repens) is also a perennial weed problem in tall fescue. In tall fescue Turflon is an effective labeled chemical control for broad leaf weeds in tall fescue. The objective of these studies was to evaluate the combination of Acclaim and Turflon to achieve improved bermudagrass control with minimal fescue injury.

Procedures

Field Study

At the South Carolina Botanical Gardens, a two year field study was initiated in May 1994 on an area of K-31 tall fescue with populations of bermudagrass and white clover. Plots were 7 feet by 7 feet and arranged in a completely randomized block experimental design with 4 replications. Treatments were Acclaim 0.38 lb ai/ A, Turflon 1.0 lb ai/ A, Acclaim 0.38 lb ai/ A + Turflon 1.0 lb ai/ A, and an untreated control. Treatments were applied with a CO2 backpack sprayer four times in 1994 and 1995 on monthly intervals beginning in May. Turf was maintained at 3 inches by gardens staff. Monthly visual evaluations for bermudagrass control, white clover control, and fescue injury were made on a scale of 0 to 100% with 0= no injury and 100= complete control. Data was evaluated by analysis of variance and means separated by LSD at P= 0.05.

Greenhouse Study

In November 1995 a greenhouse study was initiated to determine synergism or antagonism with Acclaim / Turflon combinations. Two inch plugs of common bermudagrass and K-31 tall fescue were potted into 1 quart containers with soilless media. Bermudagrass and fescue plugs were allowed to acclimatize in the greenhouse for 1 month before herbicide application. Experimental design was a complete randomized block with five replications. Treatments included: Acclaim 0.125, 0.25 and 0.38 lb ai/ A, Turflon 0.5 and 1.0 lb ai/ A, combinations of all rates and an untreated control. Visual bermudagrass control evaluations were taken on a scale of 0 to 100%, with 0= no control and 100= complete control / death, also clipping fresh and dry weight data was collected for bermudagrass and fescue. Percent inhibition was determined from dry weight data for synergism or antagonism calculations. An analysis of variance was performed and means separated by LSD at P= 0.05.

Table 1. Bermudagrass Control in Tall Fescue with Acclaim and Turflon : 1994

Table 2. Bermudagrass Control in Tall Fescue with Acclaim and Turflon : 1995

Table 3. White Clover Control in Tall Fescue with Acclaim and Turflon : 1995

Figure 1. Bermudagrass Control with Acclaim and Turflon: Greenhouse Study, 10 DAT.

Figure 2. Bermudagrass Control with Acclaim and Turflon: Greenhouse Study, 40 DAT.

Figure 3. Bermudagrass Recovery with Acclaim and Turflon: Greenhouse Study, 53 DAT.