Full TGIF Record # 240493
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Publication Type:
Author(s):Goetze, N. R.
Author Affiliation:Department of Agronomy, Purdue University, Lafayette, Indiana
Title:Poa annua control in turf
Section:Weed control in turf
Other records with the "Weed control in turf" Section
Meeting Info.:St. Louis, Missouri: December 11-13, 1961
Source:EighteenthAnnual Research Report: North Central Weed ControlConference. 1958, p. 36-37.
# of Pages:2
Publishing Information:[Lincoln, Nebraska]: [North Central Weed Science Society]
Keywords:TIC Keywords: Application timing; Arsenicals; Herbicide evaluation; Organic herbicides; Poa annua control; Recommendations
Abstract/Contents:"Poa annua develops one of the best quality turf covers known in the cool season turf belt. Unfortunately it is an annual and completes its life cycle in hot dry periods of midsummer. During cool or moist seasons the period between death of the previous crop and germination of the new one is often shortened. In the more southern locations, length of period between successive crops of Poa annua becomes longer and then problem increases in severity. The enthusiasm for classifying Poa annua as a serious turf weed therefore caries with the individual season and geographical location. This study has been based on the premise that because of its inconsistencies Poa annua should be controlled or restricted to encourage the more desirable turf species. Also the restriction of the Poa annua should come at a time in the season when the desirable turf grasses are best able to fill the vacancies formerly occupied by the Poa annua. Extensive field and greenhouse testing has demonstrated that selective removal of this weedy grass from other turf grasses is possible. A screening trial included 23 experimental herbicides applied at five different times during the growing season of 1955-56 demonstrated that Poa annua could be selectively controlled in turf. Four organic herbicides from the original group of 23 showed satisfactory selectively between Poa annua and Poa pratensis. They were CDAA at 6 lb/A, a mixture of trichlorobenzoic acids composed primarily of 2,3,6-TBA at 2 lb/A, P,P-disbutyl-N,N-diisopropylphosphinic amide at 4 lb/A, and neburon at 4 lb/A. Both calcium and lead arsenate also were active in these tests. Later experiences with CDAA and related compounds were disappointing because of damage to desirable turf. Pelleting of the materials to avoid contact injury by the carrier resulted in a product which was generally not effective on Poa annua. P,P-disbutyl-N,N-diisopropylphosphinic amide was discarded from the trials because of rather inconsistent results. 2,3,6-TBA under closer observation generally was not completely effective and also caused some damage. Neburon at 4 lb/A has satisfactorily controlled Poa annua in bluegrass lawns but damages both fineleafed fescues and bentgrasses. It is most effective when applied pre-emergence but also seems to be active on young plants as a post-emergence spray. In a few isolated instances it has selectively killed Poa annua when applied while Poa annua was in bloom. Under turf conditions, its residual activity is short and two applications per year are suggested. For control of Poa annua in turf containing fine leaf fescues or bentgrasses the inorganic arsenical materials have shown the greatest degree of success. Earlier work has shown that toxic quantities of arsenic can be built up on the soil surface layers. Germinating seedlings of Poa annua then pick up small amounts of arsenic and are killed at a young age. This method involves rather large amounts of material (120-200 pounds of metallic arsenic per acre). Since Poa annua germinates over a long period, the results are not too striking immediately. Recent trials have tested various formulations of inorganic arsenicals applied just prior to the early fall germination period. (August 15-18). Preliminary results on October 31 indicated that the materials having higher percentages of water soluble arsenic had reduced the new stands of Poa annua by 50% with no damage to the bentgrass putting green surface. Materials having smaller amounts of water soluble arsenic were not as immediately effective, but the Poa annua was beginning symptoms of arsenic toxicity. Damage to the bentgrass was neglible [negligible] in the Northern Illinois locations but the damage increased in the St. Louis area. In all but one location the severity of damage to the bentgrass was directly related to the water soluble arsenic caused the most bentgrass damage. It was hypothesized that since most of the active bentgrass roots were located in the heavy mat, arsenic materials which remained in the mat zone for the longest period were the most damaging. Compounds having high water solubility could have moved quickly through the mat with damage while those moving more slowly could have remained in the root zone sufficiently long to cause damage to the bentgrass. This work has indicated that Poa annua can be controlled in most northern turfgrass situations. The control measures are usually not 100% effective and repeated treatments may be needed. The use of herbicides is not a panacea for Poa annua control but instead is one of more important factors of good management."
Note:This item is an abstract only!
ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Goetze, N. R. 1958. Poa annua control in turf. Proc. North Cent. Weed Sci. Soc. p. 36-37.
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MSU catalog number: SB 610 .N6
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