Full TGIF Record # 56431
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Publication Type:
i
Report
Content Type:Abstract or Summary only
Author(s):Kelly, S. T.; Coats, G. E.
Author Affiliation:Department of Plant and Soil Sciences, Mississippi State University, MS
Title:Triazine-resistant annual bluegrass in Mississippi turfgrass
Meeting Info.:51st Annual Meeting, Birmingham, AL, January 26-28, 1998
Source:Southern Weed Science Society Proceedings. Vol. 51, 1998, p. 71.
Publishing Information:Champaign, IL: Southern Weed Science Society.
# of Pages:1
Keywords:TIC Keywords: Triazines; Herbicide resistance; Poa annua; Simazine; Preemergence herbicides; Application rates
Abstract/Contents:"Two populations of annual bluegrass (Poa annua L.) located in Tupelo or Meridian, MS, were evaluated for possible risistance to simazine. Questionnaires answered by the superintendents of the two golf courses revealed that simazine had been applied at least 12 consecutive years. Initial screenings at each location included applications of simazine in addition to that applied by the superintendents. Total simazine applied as : 2240, 4480, 8960, or 11200 g ai/ha. No symptoms were observed at either location with any simazine rate. Plants were taken from plots treated 11200 g/ha simazine, reared at Mississippi State, and seed collected for determination of whole-plant resistance levels. Additional field experiments evaluated 1400, 2800, 5600, or 11200 g ai/ha atrazine or diuron, 560 g ai/ha pronamide, or 1120 or 2240 g ai/ha ethofumesate for control of these populations. Atrazine did not produce symptoms on either population at any rate evaluated. Diuron controlled either population with at least 2800 g/ha. While pronamide or ethofumesate did not provide acceptable control by 31 days after treatment, some activity was observed. A second set of experiments was conducted to evaluate PRE herbicides with differing modes of activity for control of these two populations. Treatments included 560 or 840 g ai/ha prodiamine, 280 or 560 g ai/ha dithiopyr, 1680 or 3360 g ai/ha oryzalin, pendimethalin, or oxadiazon. Treatments were applied in September, 1997. Any treatment except 1680 g/ha pendimethalin controlled this this triazine-resistant population at least 83% at 102 DAT. This experiment was duplicated on the Tupelo population; however, the superintendent subsequently applied prodiamine to the test area, invalidating any results at this location. Seed collected from each of these locations were used to determine whole-plant levels of resistance. Seed was planted on a synthetic growth medium (Phytagel®) in clear air-tight trays that contained 0, 0.001, 0.01, 0.1, 1, 10 or 100 mM concentrations of simazine. Diuron was also used since it is a photosynthesis inhibitor, but has a differnet binding site on the D1 protein complex. Diuron concentrations were: 0, 0.01, 0.1, 1, 10, 100 or 1000 ΜM. Seedlings were allowed to grow for three weeks, then fresh weight of five plants were taken. These data were transformed to percent reduction compared to the untreated and subjected to regression analysis to determine the concentration of simazine or diuron required to inhibit growth 50%. The experiment was repeated and results pooled. These data indicate a greater than 100 fold level of resistance to simazine in either population. The effect of diuron on the resistant biotypes was similar to that observed on the susceptible biotype."
Language:English
References:0
Note:This item is an abstract only!
ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Kelly, S. T., and G. E. Coats. 1998. Triazine-resistant annual bluegrass in Mississippi turfgrass. South. Weed Sci. Soc. Proc. 51:p. 71.
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