Don’t waste the January opportunity to control grass-weeds in winter oilseed rape
Whilst many growers got their winter oilseed rape herbicides on last autumn, there are also many who have waited for canopies to open up in forward crops, or for the variable growth stages of the crop to even up or for the conditions to improve. Whatever the reason, January offers growers the opportunity to get on with applying an effective residual treatment with propyzamide to gain control of grass-weeds and deal with resistance issues at the same time, says Interfarm UK Ltd.
Dr. David Stormonth, Technical Manager of Interfarm UK Ltd, points out that with tightening rotations due to the increased cereal area being grown, effective grass-weed control will become all the more critical, especially if cereal grass-weed herbicides become less effective. "Opportunities to control black-grass will be reduced within the rotation, so it is important not to waste any opportunity to get on top of weeds. The January weed control opportunity in oilseed rape is one not to be missed."
"Propyzamide, as in Flomide or Engage, 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. Frosts are not necessary for propyzamide to work but degradation of the herbicide in the soil is temperature-related, so lower temperatures will mean longer persistence. Propyzamide works perfectly well at lower temperatures, but when it is colder the weed control symptoms take longer to be seen. Trials and commercial experience show that effective weed control can still be achieved from applications right up to the end of January,"
"Propyzamide is a residual soil-acting herbicide, taken up by the weed roots, so larger grass-weeds with big root systems might be best tackled with a tank mix of propyzamide and a contact-acting graminicide. Even if the grass-weed, particularly black-grass, is known to have fop-dim resistance, the addition of a fop-dim type graminicide can still slow up the weed growth rate and allow the propyzamide to take over the job of control. Propyzamide is a useful chemical to integrate into any herbicide programme as it suffers no known weed resistance. In recent trials on a range of resistant weed strains, propyzamide has still achieved total control," says Dr. Stormonth.
"January may be a dark cold month but it can offer growers an ideal opportunity to tackle the most serious grass-weed in UK agriculture," concludes David.
Propyzamide is available from Interfarm as Engage (50% WP) (which has been rebranded this year from Propose) and Flomide (400 g/litre SC). Both are 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. Interfarm recommends using the higher label dose rates to gain maximum persistence and control of black-grass. For Flomide this is 2.1 litres/ha and for Engage 1.7kg/ha. Engage and Flomide are compatible with relevant pyrethroid insecticides, graminicides and fungicides including Quell Flo (mancozeb).
