Response of Bermudagrass (Cynodon Spp.) to CGA 163935

Abstract

CGA 163935 was evaluated for its growth regulating effect on common bermudagrass for two years and ‘Tifway’ bermudagrass for four years. The vegetative growth of mowed common bermudagrass was suppressed for 5 wk when CGA 163935 was applied at 0.2 kg ha–1 followed by 0.1 kg ha–1 2 wk later and mowed Tifway bermudagrass was suppressed for 4 wk after application of 0.2 kg ha–1. CGA 163935 suppressed vegetative growth of non-mowed common bermudagrass for 9 wk and non-mowed Tifway bermudagrass for 2 to 8 wk at the same rates. Common bermudagrass tolerated CGA 163935 when applied initially at 0.2 kg ha–1 and followed by 0.1 kg ha–1 at a 2-wk interval for a total 0.3 kg ha–1 rate. However, common bermudagrass was severely injured (> 30%) when CGA 163935 was applied at 0.2 kg ha–1 in each of two applications for a total rate of 0.4 kg ha–1. Tifway bermudagrass tolerated CGA 163935 when applied at 0.2 kg ha–1 as a single application or when the 0.2 kg ha–1 was followed by 0.1 kg ha–1 at a 4-wk interval. Tifway bermudagrass was severely injured (> 30%) when CGA 163935 was applied at 0.4 kg ha–1 as a single application or when 0.2 kg ha–1 was followed by 0.1 kg ha–1 at 2- or 3-wk interval. Seedheads were suppressed in common bermudagrass for 1 to 2 wk with CGA 163935 at 0.4 kg ha–1.