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| Publication Type:
| Report |
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| Content Type: | Abstract or Summary only |
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| Author(s): | Yelverton, F. H.;
Isgrigg, John |
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| Author Affiliation: | Department of Crop Science, North Carolina State University, Raleigh, NC 27695-7620 |
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| Title: | Effects of plant growth regulators on suppression of Poa annua spp. reptans in bentgrass greens |
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| Meeting Info.: | 50th Annual Meeting, Houston, TX, January 20-22, 1997 |
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| Source: | Southern Weed Science Society Proceedings. Vol. 50, January 1997, p. 68-69. |
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| Publishing Information: | Champaign, IL: Southern Weed Science Society. |
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| # of Pages: | 2 |
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| Abstract/Contents: | "Annual bluegrass (Poa annua) continues to be problematic in highly-maintained turfgrasses. There are many different biotypes of annual bluegrass found in southern turfgrasses. Those biotypes that tend to die with warm weather in the spring and the summer act as true annuals and are referred to as Poa annua spp. annua whereas those that survive the summer temperatures act as perennials and are referred to as Poa annua spp. reptans. The annual biotypes can be found in any turf type at any mowing height in the southern U.S. However, the perennial biotypes are generally only found in putting greens or in other very high maintenance situations. The fact that many (perhaps hundreds) of annual bluegrass biotypes exist makes successful management of this weed very difficult. On bentgrass (Agrostis palustris) putting greens, the perennial biotypes cannot be controlled by the same herbicides that may prevent germination of the annual biotypes. Previous research has shown that gibberellic acid (GA) inhibiting plant growth regulators (PGRs) can be utilized to help shift the competitive edge away from annual bluegrass in favor of bentgrass. Two field trials were initiated in the fall of 1995 to evaluate trinexapac-ethyl (a new GA inhibiting PGR), flurprimidol, and paclobutrazol as fall and spring applications to suppress Poa annua spp. reptans in bentgrass putting green. One test involved overseeding in early September with bentgrass and the other test did not involve overseeding. The purpose of this was to evaluate whether overseeding with bentgrass may enhance transition from bluegrass to bentgrass. The tests were conducted on two unamended managed greens at Wake Forest Country Club that were heavily infested with Poa annua spp. reptans. Plot sized was 5x5 ft and treatments were arranged in a randomized complete block design with 4 replications. Treatments were trinexapac-ethyl applied (in lbs ai/a) at 0.1 in the fall (September 5) and spring (March 12), 0.17 in fall and spring; two fall applications at 0.1 plus 0.05 four weeks after the initial application followed by 0.1 in the spring, and 0.17 plus 0.05 four weeks after the initial application followed by 0.17 in the spring. Paclobutrazol was applied at 0.375 lbs ai/a on October 3 followed by the same rate on November 1 and March 12. Flurprimidol was applied at 0.25 lbs ai/a on September 5 followed by the same rate on March 12. Trinexapac-ethyl was applied in 33 gallons per acre (gpa) and paclobutrazol and flurprimidol were applied in 66 gpa. All treatments were applied with XR8002 flat fan nozzles at 26 pounds per square inch. Poa annua spp. reptans populations were evaluated in each plot on September 5 and on April 16. In the overseeded bentgrass green, the annual bluegrass population in nontreated plots increased from 78 to 85% from September to April. Trinexapac-ethyl or flurprimidol treatments did not affect Poa annua spp. reptans populations from fall to spring. Paclobutrazol treatments reduced annual bluegrass populations from 91 to 60% from fall to spring. Paclobutrazol and the highest trinexapac-ethyl treatment regime suppressed annual bluegrass seedheads by 98 and 71%, respectively when visually rated on April 16. Flurprimidol suppressed seedheads by 55%. On the nonoverseeded green, annual bluegrass populations in nontreated plots increased from 46 to 70%. Trinexapac-ehtyl treatments did not affect annual bluegrass populations whereas paclobutrazol reduced the population from 49 to 34% and flurprimidol kept the annual bluegrass population from significantly increasing (45 to 49%). Paclobutrazol, flurprimidol, and the highest trinexapac-ethyl treatment regime suppressed seedheads 80, 48, and 45%, respectively. At the rates tested in these experiments, paclobutrazol had the most effect on Poa annua spp. reptans populations followed by flurprimidol while trinexapac-ethyl had the least effect. These results indicate trinexapac-ethyl rates and/or treatment intervals must be increased/shortened to affect suppression of Poa annua spp. reptans in bentgrass putting greens. |
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| Language: | English |
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| References: | 0 |
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| See Also: | See also complete report in Science and Golf III, 1999, p. 647-654, R=60685 R=60685 |
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| See Also: | Other items relating to: P G Rs 1997-2006 |
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| Note: | This item is an abstract only! |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Yelverton, F. H., and J. Isgrigg. 1997. Effects of plant growth regulators on suppression of Poa annua spp. reptans in bentgrass greens. South. Weed Sci. Soc. Proc. 50:p. 68-69. |
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