| Abstract/Contents: | "Annual bluegrass (Poa annua) is an annual grass weed common in various turfgrass situations. Annual bluegrass has an off-yellow color that can disrupt uniformity, produce noxious seedheads, and germinate throughout winter. More importantly, this species has broad genetic diversity which has led to an increase in resistant populations. The purpose of this research is to screen various products for annual bluegrass control in non-overseeded and overseeded bermudagrass. Two studies were conducted at Clemson University to investigate the efficacy of various herbicides on annual bluegrass control in non-overseeded and overseeded bermudagrass, and evaluate any effects the products may have on bermudagrass green-up. Study one was conducted on nonoverseeded, dormant common bermudagrass at the Clemson University band field. Study two was conducted on overseeded Tifway bermudagrass at Boscobel Golf Course, Pendleton, SC. Plot sizes for each treatment were 2.0 m by 2.0 m, and replicated three times. Treatments were applied using a CO2 backpack sprayer calibrated at 20 GPA, at 30 PSI, with 8003 flat fan spray tips. Treatments for study one included: Barricade, Dimension, Pendimethalin, Surflan, Bensulide, Simazine, Ronstar, Balan, Regal Star, Kerb, and Plateau. Treatments for study two included: Dimension, Barricade, Kerb, Ronstar, TranXit, Prograss, and Bensulide. Ratings for annual bluegrass control were based on a scale of 0-100%, with 0% representing no control and 100% representing complete control. Any rating recorded below 90% was deemed unacceptable. Green-up ratings of common bermudagrass were based on a scale of 0-100% with 0% representing no green-up and 100% representing complete green-up. On the final rating date (April 28, 2003) for study one, Barricade (65 WG) at 0.75 lb ai/a (August-2002), Barricade at 0.75 lb ai/a (August-2002) fb Barricade at 0.38 lb ai/a (January-2003), Surflan (4 AS) at 3.0 lbs ai/a (August-2002), Surflan at 3.0 lbs ai/a (August-2002) fb Surflan at 1.5 lbs ai/a (January-2003), Simazine (4 L) at 2.0 lbs ai/a (August-2002) fb 1.0 lb ai/a (January-2003), Ronstar (2 G) at 2.0 lbs ai/a (August-2002), Ronstar at 2.0 lbs ai/a (August-2002) fb 1.0 lb ai/a (January- 2003), Regal Star (1.2 G) at 3.0 lbs ai/a (August-2002), Regal Star at 3.0 lbs ai/a (August-2002) fb 1.5 lbs ai/a (January-2003), Kerb (50 WP) at 2.0 lbs ai/a (November-2002), and Plateau (2L) at 0.1 lb ai/a (November-2002 fb January-2003 fb February 2003) treatments provided >90% control. Pendimethalin (60 WG) at 3.0 lbs ai/a (August-2002) fb 1.5 lbs ai/a (January-2003) and Balan (1.5 EC) at 3.0 lbs ai/a (August-2002) fb 1.5 lbs ai/a (January-2003) treatments provided 70-80% control. Also, a delay in common bermudagrass green-up (12%) was observed with Plateau treatment. On the final rating date (April 21, 2003) for study two, Barricade (65 WG) at 0.5 lb ai/a (60 DBO) fb 0.5 lb ai/a (January-2003) and Prograss (1.5 EC) at 1.0 lb ai/a (45 DAO) fb 1.0 lb ai/a (December- 2002) treatments provided >90% control. Dimension (40 WP) at 0.5 lb ai/a (45 DBO) fb 0.5 lb ai/a (January-2003), Dimension at 0.5 lb ai/a (45 DBO) fb Prograss (1.5 EC) at 1.0 lb ai/a (December- 2002), Barricade at 0.5 lb ai/a (60 DBO) fb Prograss at 1.0 lb ai/a (December-2002), Kerb (50 WP) at 2.0 lbs ai/a (45 DBO) fb Prograss at 1.0 lb ai/a (December-2002), and Ronstar (2G) at 2.0 lbs ai/a (45 DBO) fb Prograss at 1.0 lb ai/a (December-2002) provided 80-90% control. Kerb at 2.0 lbs ai/a (45 DBO), Ronstar at 2.0 lbs ai/a (45 DBO), TranXit (25 DF) at 0.03 lb ai/a (14 DBO), and TranXit at 0.03 lb ai/a (14 DBO) fb Prograss 1.0 lb ai/a (December-2002) treatments provided 70-80% control. Future research should screen new products for annual bluegrass control in various turfgrass situations. Furthermore, different combinations of treatments and sequential treatments, and altering the timing of application should be evaluated." |
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