Top ten tips to get the best from propyzamide

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Follow these guidelines to get top results:

  • Performance is best where rape crops have been established using min-til techniques.Black-grass seeds remain and then germinate in the top layers of the soil where the propyzamide is retained.


  • Applications should be made to firm, moist soils with a fine tilth where possible.
  • Propyzamideis best applied when soil temperatures have got down to 10oC at 30 cms and are falling to avoid too rapid degradation.The half-life of propyzamide at 10ºC is around 100 days whereas at 15ºC it falls to 60 days. Hence the need for cooler soils. Good grass-weed control is achieved when a lethal concentration of propyzamide is reached in the germinating weed. This is a function of plant size, rate of growth and continuing availability of propyzamide in the top 5cm or so of the soil for uptake.
  • Kerb (propyzamide) may be applied in frosty conditions, but avoid application onto frozen ground where subsequent rainfall could result in run-off into watercourses. For ASTROKerb(propyzamide and aminopyralid), ideally ensure frost is off the target broad-leaved weeds. There needs to be sufficient moisture in the soil for plant uptake, but avoid water logged or saturated soils.Soil moisture deficit should be less than 50mm and falling.
  • Our data shows that the combination of optimal weather and soil conditions usually starts after the 5thNovember in a normal year. Products containing propyzamide (Kerb Flo 500 and ASTROKerb) have a wide window of usage up until 31st.
  • Where there are populations of difficult to control black-grass, use the maximum label rate of propyzamide (850 gai/hectare). Propyzamide will control black-grass resistant to other chemistries in the arable rotation and for this reason is an important tool in managing black grass populations.
  • Strategic use is recommended in tank mix or sequences with graminicides. In very difficult black-grass situations, adding a “dim” to Kerb Flo 500 or ASTROKerb nearly always raises the level of weed control. Alternatively, independent trials have proven how effective a programme of clethodim followed by Kerb Flo or ASTROKerb can be in controlling high levels of black-grass in oilseed rape crops. Applications of clethodim should be made in October followed, at least 14 days later, by Kerb Flo 500 or ASTROKerb in November. Clethodim cannot be tank mixed with Kerb or ASTROKerb.
  • Propyzamide is soil acting so spraying wet weeds at run-off or light rainfall after application is not an issue. ASTROKerbis rainfast after1 hour.
  • All applications should be made with due regard to water stewardship, i.e. do not spray where there is a risk of run-off to adjacent watercourses.

Iuliia Kovalova, of Corteva Agriscience, the Agriculture Division of DowDuPont, comments “Propyzamide is an important active ingredient for use in an arable cereal/rape rotation as it controls all black-grass types as well as rye-grass and other grass weeds .When given the best conditions to work, propyzamide can give high levels of black-grass control of over 90%, thus helping to reducing the weed population across the farm and giving higher levels of control than are often achieved in cereals,” she concludes.


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