Invasive Species Compendium

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Abstract

Dallisgrass (Paspalum dilatatum) control with foramsulfuron in bermudagrass turf.

Abstract

Dallisgrass (P. dilatatum) response to various MSMA and foramsulfuron combinations was evaluated in hybrid bermudagrass (Cynodon transvaalensis Ă— C. dactylon) from 2004 through 2006 in North Carolina, USA. Dallisgrass control declined with the herbicide rates; therefore, only the highest rates (foramsulfuron, 0.15 kg a.i./ha, and MSMA, 2.5 kg a.i./ha) were considered. Foramsulfuron followed by (fb) foramsulfuron at one week after the initial treatment (WAIT) provided 60% control of dallisgrass at one month after the initial treatment (MAIT), but control declined to 40% at 3 MAIT. MSMA (2.5 kg a.i./ha) applied 3 times provided 89% dallisgrass control at one MAIT, but the control declined to 71% at 3 MAIT. Among the 22 MSMA and foramsulfuron sequential application programmes, MSMA fb foramsulfuron at 2 WAIT fb MSMA at 3 WAIT provided the highest control (94%) of dallisgrass at one MAIT, and the control levels remained high (93%) at 3 MAIT. This herbicide programme provided 85% control at one year after the initial treatment (YAIT), whereas no other treatment provided greater than 37% control at one YAIT. The timing of foramsulfuron application following initial MSMA application affected the control of dallisgrass. Delaying the application of foramsulfuron until 2 WAIT rather than one WAIT increased the control of dallisgrass by 20% at one MAIT and 19% at 3 MAIT. However, the increase in the control at one YAIT was only 5% regardless of the herbicide rate. The addition of a second application of MSMA following the application of foramsulfuron at 2 WAIT of MSMA further increased control by 10% at one MAIT, 37% at 3 MAIT, and 48% at one YAIT. The results suggested dallisgrass may be controlled with the application of MSMA fb foramsulfuron at 2 WAIT fb MSMA at 3 WAIT applied during early to mid-summer. The use of MSMA was required to achieve dallisgrass control; however, the relatively high level of control achieved at one YAIT with a programme including sequential applications of MSMA and foramsulfuron may help reduce the total amount of arsenical herbicides used to control dallisgrass infestations over time.