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| Web URL(s): | http://www.newss.org/proceedings/proceedings_1992_vol46.pdf#page=14
Last checked: 07/24/2013
Requires: PDF Reader
Notes: Item is within a single large file |
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| Publication Type:
| Report |
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| Content Type: | Abstract or Summary only |
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| Author(s): | Koo, S. J.;
Webber, N. D.;
Neal, J. C. |
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| Author Affiliation: | Cornell University--Graduate Students; Assoc. Professor |
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| Title: | Variability in the efficacy of BAS 514..H on crabgrass |
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| Source: | Proceedings of the 46th Annual Meeting of the Northeastern Weed Science Society. Vol. 46, 1992, p. 14. |
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| Publishing Information: | Ithaca, NY: Northeastern Weed Science Society |
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| # of Pages: | 1 |
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| Keywords: | TIC Keywords: Digitaria ischaemum; Quinclorac; Field capacity; Drought; Herbicides; Irrigation
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| Abstract/Contents: | "BAS 514..H (quinclorac) is regarded as a promising herbicide for the control of crabgrass (Digitaria spp.) in turf. However, the efficacy of BAS 514 on crabgrass has been inconsistent among several different field locations. The causes of this variability are unclear. The effects of the potential variables such as irrigation schedule, drought, spray coverage, biotype differences in susceptibility, and growth stages of smooth crabgrass [Digitaria ischaemum (Schreb. ex Schweig) Schreb. ex Muhl] were investigated. The influence of irrigation was examined in the field which was under drought, from June to July 1991. BAS 514 (0.8 kg/ha) was sprayed at -2, -1, 0, 1, 2, or 4 days after irrigation and the efficacy was visually evaluated 4 wk after application. The effect of drought and/or spray coverage was studied in lysimeters, once in a rain exclusion shelter and repeated in a growth chamber at 25 degrees C. Smooth crabgrass seedlings were transplanted into lysimeters at the 2-leaf stage. Plants were grown until the 2-tiller stage. Two watering regimes were compared: (1) field capacity and (2) dried to about -15 bars plant water potential. BAS 514 was applied at 0.6 or 0.8 kg/ha to either the foliage, soil, or both, by soil surface coverage with vermiculite, plant coverage with small test tubes, or no coverage, respectively. Seven or three days after BAS 514 application (in the rain exclusion shelter or in the growth chamber, respectively), drought treatments were watered and thereafter maintained at field capacity. The efficacy was visually evaluated at 1 wk intervals. Seed from two sources, Ithaca, New York and Columbus, Ohio were compared for differences in 50% or 90% inhibition rates (I[subscript]50 or I[subscript]90). Two-leaf, 3-leaf, 1-tiller and 2-tiller stage plants of both biotypes were sprayed with several rates of BAS 514. After 2 wk, remaining green shoots were excised for the fresh weight measurement, and the I[subscript]50 and I[subscript]90 for each biotype and stage were calculated. Irrigation schedule under drought conditions greatly affected the efficacy of BAS 514. When applied after irrigation, good to excellent control was obtained, however, when applied before irrigation, virtually no control was observed. The optimum time of irrigation was 2 to 4 days before BAS 514 treatment. Drought decreased the efficacy of BAS 514 significantly in the lysimeter experiments. The efficacy decreased more with foliar applications than with soil applications. Regardless of the water regime, the efficacy of foliar applications was greatest 2 wk after application, and then decreased. Control with soil applications was much slower, with symptoms beginning about 2 wk after application and increasing to a maximum 4 wk after treatment. Biotype differences in susceptibility were not significant up to the 1-tiller stage. However, at the 2-tiller stage, the New York biotype was more tolerant than the Ohio biotype with I[subscript]90 of 472 and 400 g/ha for New York and Ohio biotypes, respectively. the application rate to achieve 90% control increased as growth stage advanced. These results show that the efficacy of BAS 514 is greatly affected by drought. BAS 514 efficacy was also affected by application method, biotype, and growth stage of smooth crabgrass. To overcome this variability, pre-irrigation is suggested to enhance the efficacy under drought conditions. Further research is needed to define methods for enhancing BAS 514 efficacy where scheduled irrigation is not possible. These data suggest that when irrigation is not available, root-targeted treatments or application methods which enhance foliar activity should be investigated." |
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| Language: | English |
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| References: | 0 |
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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):
Koo, S. J., N. D. Webber, and J. C. Neal. 1992. Variability in the efficacy of BAS 514..H on crabgrass. Proc. Annu. Meet. Northeast. Weed Sci. Soc. 46:p. 14. |
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| Web URL(s):
http://www.newss.org/proceedings/proceedings_1992_vol46.pdf#page=14
Last checked: 07/24/2013
Requires: PDF Reader
Notes: Item is within a single large file |
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MSU catalog number: SB 610 .N62 |
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