| Abstract/Contents: | "Most large bermudagrass turf areas established from sprigs. Although economical, sprigged areas are thin in terms of stand density for a considerable time following planting. This allows encroachment of several persistent annua weeds such as goosegrass and crabgrass. Research was performed to evaluate: a) Tifway (419) bermudagrass establishment following preemergence herbicide application made either one day before of after sprigging, and b) control of goosegrass (Eleusine indica ELEIN), annual sedge (Cyperus compressus CYPCO), and sicklepod (Cassia obtusifolia CASOB). Plot size was 3.3 x 6.6m. A RCB design was used with four relicates. Sprayable herbicides were applied in 187 L/ha of water and irrigated immediately following treatment with 1/2 inch. Herbicides were applied either one day prior to or after sprigging performed by a commercial planter at 400 bushels of sprigs per acre. Percent weed control and turf cover were estimated visually. Percent bermudagrass cover was highest for the untreated two (35%) and four (72%) weeks after treatment (WAT). This was followed by oxadiazon G (3.36 kg ai/ha) and simazine (1.0 kg/ha) at 2WAT (18 and 17%) and at 4 WAT (41 and 34%, respectively). At 8 WAT, percent turf cover was highest from the untreated (92%) followed by simazine (88%) and oxadiazon G (86%). At 12 WAT, highest turf cover resulted from the untreated (95%), oxadiazon G (94%) simazine (91%), metolachlor at 2.24 kg/ha (90%), and oxadiazon WP at 3.36 kg/ha (89%). These were followed by pendimethalin at 2.8 kg/ha (78%), dithiopyr at 0.56 kg/ha (66%), and prodiamine at 0.84 kg/ha (60%). Least turf cover at this time was associated with diuron at 1.68 kg/ha (24%). Contrast statements to compare application timing and herbicide formulations used revealed: higher turf cover ([approximately] 10%) resulted through 4WAT when oxadiazon was applied pre-sprigging. Cover was unaffected by oxadiazon application timing after this time. Higher turf cover also accompanied pre-sprigging treatments of simazine (7%) and metolachlor (9%) compared to post-sprigging but was significant only 2WAT. Application timing did not influence turf cover following prodiamine, dithiopyr, pendimethalin or diuron treatments. Granular oxadiazon had higher turf cover at 2WAT (8%), 4WAT (20%), and 8WAT (21%) compared to WP formulation but was similar by 12 WAT. Goosegrass control was excellent (> or = 90%) through 4WAT by all treatments. However, by 8WAT, excellent control was provided only by oxadiazon WP, metolachlor, and pendimethalin. Good control (80 to 89%) accompanied diuron, oxadiazon G, dithiopyr, and prodiamine. Unacceptable control (< 70%) followed simazine at this time. At 12WAT, only oxadiazon WP provided excellent control. Good control followed diuron, oxadiazon G, and metolachlor treatments. Fair control (70 to 80%) followed pendimethalin while poor control followed dithiopyr, prodiamine and simazine application at this time. Contrast statements revealed that application made in respect to sprigging timing and G vs. WP oxadiazon formulations did not influence goosegrass control throughout the testing period. Annual sedge control 2 and 4WAT was excellent following both oxadiazon formulations, diuron, metolachlor and simazine. Excellent control continued 8 and 12WAT by both oxadiazon formulations, diruon and metolachlor. Unacceptable control 12WAT followed simzine, dithiopyr, pendimethalin, and prodiamine. Sicklepod control 4WAT was excellent following diuron treatments, good following pendimethalin, and poor for the remaining treatments. Overall, best turf cover and goosegrass control was provided by oxadiazon and metolachlor treatments followed by pendimethalin, dithiopyr, and prodimaine [prodiamine]. Unacceptable goosegrass control and/or turf cover followed simazine and diuron treatments. Oxadiazon, metolachlor, and diuron provided best annual sedge control while diuron and pendimethalin provided best sicklepod control." |
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