2 results
Enhancement of tolpyralate efficacy with adjuvants
- John C. Fluttert, Nader Soltani, Mariano Galla, David C. Hooker, Darren E. Robinson, Peter H. Sikkema
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- Journal:
- Weed Technology / Volume 36 / Issue 2 / April 2022
- Published online by Cambridge University Press:
- 15 March 2022, pp. 310-317
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- Article
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Tolpyralate is a 4-hydroxyphenylpyruvate dioxygenase–inhibiting herbicide that is applied postemergence for control of annual broadleaf and grass weeds in corn. Current Canadian label recommendations for tolpyralate specify the addition of a methylated seed oil (MSO) adjuvant (MSO Concentrate®) for improved weed control. The efficacy of tolpyralate applied with other proprietary adjuvants has not been widely reported in the peer-reviewed literature. Therefore, four field trials were conducted in corn over 2020 and 2021 in Ontario, Canada, to evaluate MSO Concentrate®, Agral® 90 (nonionic surfactant), Assist® Oil Concentrate (blended surfactant), Carrier® (blended surfactant), LI 700® (nonionic surfactant), and Merge® (blended surfactant) as adjuvants with tolpyralate for the control of annual broadleaf and grass weeds. At 8 wk after application (WAA), tolpyralate applied with MSO Concentrate®, Agral® 90, Assist® Oil Concentrate, Carrier®, or Merge® controlled velvetleaf, wild mustard, barnyardgrass, and foxtail species similarly. These adjuvants also enhanced the efficacy of tolpyralate similarly for the control of common ragweed at 8 WAA with the exception that Agral® 90 was inferior to Merge®. At 8 WAA, tolpyralate controlled common lambsquarters the greatest when applied with MSO Concentrate®, Agral® 90, Carrier®, or Merge®; these adjuvants with the exception of Agral® 90 were superior to Assist® Oil Concentrate. At 8 WAA, tolpyralate applied with LI 700® controlled common ragweed, barnyardgrass, and foxtail species less than when tolpyralate was applied with the other adjuvants tested; control of these weed species with tolpyralate was not improved with LI 700® when compared to tolpyralate applied without an adjuvant. Overall, tolpyralate applied with either MSO Concentrate®, Carrier®, or Merge® controlled all annual broadleaf and grass weed species similarly or greater than tolpyralate applied without an adjuvant or tolpyralate with Agral® 90, Assist® Oil Concentrate, or LI 700® at 8 WAA.
Weed seedbank dynamics in post conservation reserve program land
- Joel Felix, Micheal D. K. Owen
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- Journal:
- Weed Science / Volume 49 / Issue 6 / December 2001
- Published online by Cambridge University Press:
- 20 January 2017, pp. 780-787
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The influence of tillage, crop rotation, and weed management regimes on the weed seedbank in land previously under the conservation reserve program (CRP) for 8 yr was determined from 1994 through 1997. The study was a split-plot design with four replications, two tillage systems, two crop rotations, and three weed management treatments. Eleven weed species were recorded in 1994 and 1995, and 13 in 1996 and 1997. The weed seedbank was dominated by broadleaf species. In 1994, the first year after CRP, the seed population density in the top 15 cm of the soil profile was 51,480 seeds m−2, of which 60 and 20% were pigweed and common lambsquarters. The population density of pigweed seeds in the seedbank increased over time and reached 51,670 seeds m−2 in 1996. In contrast, the seed population density for foxtail species was only 417 seeds m−2 in 1994, but it increased to 7,820 seeds m−2 in 1997. The large increase in foxtail species seed population density in the 4-yr period was mainly in the no-herbicide weed management treatment. The weed seedbank was reduced similarly by band and broadcast herbicide treatments. Tillage and crop rotation did not influence the weed seedbank or Shannon's diversity index, nor did they interact with the weed management treatments in any of the years. The weed seedbank population density varied with the years and time of soil sampling. Weed seed population densities tended to be greater in the fall but declined significantly by time of the spring sampling. The no-herbicide treatment had a more diverse weed seedbank compared with band and broadcast herbicide weed management treatments. An average of one grass and three broadleaf weed species were identified in the three weed management treatments. Band and broadcast herbicide treatments reduced the weed seedbank population density but did not affect the number of broadleaf weed species observed.