The New Year, and January in particular, offers a key spray opportunity for the residual herbicide Kerb in winter oilseed rape and this opportunity to control grass-weeds and deal with resistance issues mustn’t be missed, says Dow AgroSciences.
Rene Pollak of Dow AgroSciences points out that after Christmas, oilseed rape growers have a short but ideal weed control window during January. "Trials and commercial experience show that effective weed control can still be achieved from applications of Kerb right up to the end of the month and this opportunity shouldn’t be over-looked. In fact January applications are particularly effective because grass-weeds develop adventitious roots that pick up sufficient active ingredient. Often at this time the crop has opened up through winter die-back, allowing a more even application of Kerb Flo across the soil surface, which is ideal."
"Kerb remains one of the most highly effective herbicides against black-grass and can be applied up to the end of January, even in frosty weather. Applications are best made when soil temperatures are declining, with the target optimum temperature of 10°C and falling. Best results are achieved when growth of weeds, especially black-grass and volunteer cereals, is slow but transpiration continues. Lower temperatures means longer persistence, as degradation of the herbicide in the soil is temperature-related, but weed control symptoms will take longer to be seen," explains Rene.
He reminds growers that applications of Kerb Flo should be made when soils are moist, but not waterlogged or saturated. "A rough rule of thumb is when the soil is at 80% field capacity, but before drains are flowing. This will avoid accidental run-off. Every care must be taken to avoid any risk of contamination to waterways."
Rene Pollak points out that Kerb Flo can be mixed with a wide selection of tank-mix partners. "Mixing or sequencing with contact-acting graminicides such as cycloxydim has been shown to further enhance weed control, particularly if the grass-weed target is larger, as is normally the case at this time of year. The combination of Kerb and a fop/dim type graminicide often results in surprisingly good control, even if the black-grass is known to exhibit fop/dim resistance."
But he warns growers to use a Dow AgroSciences’ manufactured propyzamide such as Kerb which has been formulated to be easily tank-mixable and is indemnified for a wide range of compatibilities with commonly used partners. Details of Kerb Flo tank mix compatibilities can be found on the web site at www.dowagro.com/uk/tankmixsummaries.htm .
Kerb Flo (400g/L suspension concentrate) is recommended in winter oilseed rape, winter beans and a wide range of other crops for the control of cereal volunteers, annual meadow-grass, black-grass, brome, wild-oats, chickweed, bindweed, fat hen, redshank, small nettle, speedwells and black nightshade. In oilseed rape Kerb Flo has a wide window of application of four months, from the 1st of October through to the end of January. It is recommended at dose rates of 1.25 to 2.1 l/ha depending on weed species and is compatible with a wide range of graminicides, insecticides and fungicides.
