Poa annua L. is a ubiquitous cool-season turfgrass that is reported to have originated on the European continent ( Tutin, 1957 ). It is an allotetraploid (2n = 4x = 28) thought to be derived from a chance cross between Poa infirma Kunth and
Annual bluegrass ( Poa annua L.) often invades and persists in intensively managed cool-season turfgrass systems ( Beard, 1973 ). A lack of heat, drought, and disease tolerance compared with other cultivated turfgrass species makes it difficult
two blocks; however, data are nearly identical. Therefore, species color and percent ABG data will only be discussed for ‘JS501’ ( Table 2 ). Table 2. Color of ‘JS501’ and ‘Replay’ perennial ryegrass and Poa annua after four different glyphosate
Faeriefungin, an antibiotic produced by the actinomycete Streptomyces griseus var. autotrophicus MSU-32058/ATCC 53668, was tested in field trials on golf course fairways to determine if it could control annual bluegrass (Poa annua L.) summer patch effectively. Test sites with a history of severe summer patch outbreaks caused by Magnaporthe poae Landschoot and Jackson were chosen for study. Faeriefungin, when applied as a drench at 0.74 kg·ha-1, effectively controlled summer patch and was not significantly different than the fungicide fenarimol in three of four field trials. Faeriefungin may be an alternative to chemically controlling summer patch disease.
Annual bluegrass (Poa annua L.) and creeping bentgrass (Agrostis palustris Huds. syn. A. stolonifera L.) coexist on golf greens as a dynamic ecosystem in the temperate regions of the United States. In a two year field study, the competitive ability of different populations of annual bluegrass was investigated both in and out of their native environment. In April 2000, at both The Country Club in Cleveland, Ohio, a temperate environment, and Camargo Club in Cincinnati, Ohio, a transition zone environment, 72 plugs of annual bluegrass were removed from golf greens and inserted into polyvinyl chloride pipe measuring 10.2 cm in diameter and 15 cm in length to eliminate root competition between species. Thirty-six plugs then were reestablished into one of three greens at the same golf course, and the remaining 36 plugs were transported to the opposite location and also established into one of three preselected greens. Each plug was centered in a 20.3-cm-diameter sward of `L-93' creeping bentgrass to provide an initial point of reference. Competitive ability was measured as the rate of increase or decrease in average diameter of each plug. Measurements initially were taken on a bimonthly basis and then on a monthly basis for the remainder of the study. Significant (P < 0.05) differences in the location × population interaction were seen in the first 2 months of the study and then not seen again until the last 2 months. The most frequent occurrence of significant (P < 0.05) differences was in the variability between greens within a particular location. At each location the native population of annual bluegrass outperformed the imported population. Differences at the beginning of the study are attributed to an additional acclimation period required by the exported population following transportation to the opposite location. From our study, annual bluegrass performance was similar across populations, suggesting that management recommendations can be made on a regional basis.
Annual bluegrass (Poa annua L.) is an invasive weed producing copious amounts of viable seed that compete with seedling turfgrasses during renovation. These field studies were conducted to determine the effectiveness of dazomet (tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione), a granular soil sterilant that breaks down in soil to release methyl isothiocyanate (MITC), for controlling the soil seed bank of annual bluegrass during turfgrass renovation. Field trials in Urbana, Ill., and West Lafayette, Ind., in Spring and Fall 2000 and 2001 evaluated dazomet rate from 0 to 504 kg·ha-1 and soil preparation techniques to determine the most effective practices to reduce annual bluegrass reestablishment into a creeping bentgrass (Agrostis stolonifera L.) seeding. The interval, in days, between dazomet application and creeping bentgrass planting was also examined to determine the optimal seeding time as measured by the level of annual bluegrass reestablishment. Spring trials generally gave poor results that were attributed to windy conditions resulting in rapid loss of MITC. The annual bluegrass soil seed bank was reduced 46% in spring trials compared to 78% in fall trials. Increasing dazomet rates reduced the absolute number of viable annual bluegrass seeds remaining in the soil. However, significant quantities of viable seed remained, regardless of dazomet rate. Annual bluegrass infested the renovated turf in all trials to varying degrees. Dazomet rates of 420 or 504 kg·ha-1 yielded the lowest rates of annual bluegrass reestablishment. Trials conducted in the fall at these rates resulted in annual bluegrass cover of 1% to 20% in the resulting turf. Creeping bentgrass planted at 1 day after dazomet application had significantly less annual bluegrass than when seeded at 7 or 9 days after dazomet application. Dazomet is a tool that can help reestablish a new turf with lower levels of annual bluegrass. However, eradication of annual bluegrass with dazomet is not likely and environmental conditions will dramatically affect the success of the sterilization.
At present, there is no herbicide registered for use in Canada to control annual bluegrass in sod production. Under serious infestations, aesthetic qualities are reduced and sod harvest becomes more complicated. The efficiency of propane burners to control annual bluegrass was tested in a trial initiated in Spring 1993. Specific objectives were to determine the appropriate period for treatment application and the heat intensity required for optimal control. Twenty-one plots (13 × 3 m) were treated with a conventional burner; a similar group was treated with a pipe burner. In addition to an untreated check, the combination of two tractor-burner speeds (3.6 and 5 km·h-1) and three gas pressures (20, 30, and 40 psi) made up the seven treatments. Randomized complete blocks were used and each treatment was replicated three times. The sod recovered well from all heat treatments. After 3 weeks, the best heat treatment reduced the annual bluegrass population by 70%. Unfortunately, this reduction lasted for about 1 month, after which the annual bluegrass population recovered. At best, weed population was reduced by 40% when evaluated in mid-September. Another trial is planned to identify environmental and edaphic factors that may reduce the effectiveness of heat treatments in controlling annual bluegrass in sod production.
Annual bluegrass ( Poa annua ) is considered a most problematic annual winter weed in managed turfgrass, such as golf courses ( Cross et al., 2013 ). This weed has traditionally been controlled by herbicides; however, populations that are resistant
carefully consider using a rotation of herbicide products with different modes of action. Literature Cited Barros, M.D.C. Dyer, T.A. 1988 Atrazine resistance in the grass Poa annua is due to a single base change in the
.B. 2003 Flora of North America: North of Mexico, Vol. 25, Magnoliophyta: Commelinidae (in part): Poaceae , part 2. Oxford University Press, New York, NY Beard, J.B. Rieke, P.E. Turgeon, A.J. Vargas J.M. Jr 1978 Annual bluegrass ( Poa annua L