23-10-2009 12:43 PM | Arable, Crops, News

Wait for optimum conditions to apply residual propyzamide in rape and beans



Following a dry start to the autumn this year, Interfarm UK are advising growers to wait for optimum conditions before they apply the residual-acting herbicide propyzamide to winter oilseed rape and winter beans, whilst ensuring it is handled with care when it comes to water issues.

"The dry early autumn allowed growers to get their oilseed rape drilled in time, but many held back with their normal pre-em or peri-emergence herbicide treatments. This may mean more need for a post-em treatment, particularly when it comes to grass-weeds such as black-grass, the second flush of cereal volunteers, brome, wild-oats and annual meadow-grass and certain broad-leaved weeds such as chickweed. But growers shouldn’t rush into getting their residual-acting propyzamide herbicides, Flomide and Engage, on but rather wait for good levels of soil moisture before applying them," says Dr. David Stormonth, Technical Manager for Interfarm UK Ltd.

"Good levels of soil moisture are needed as this allows the herbicide to penetrate the top layers of the soil profile and helps weed roots take up the herbicide. Propyzamide binds strongly to soils and doesn’t leach and so rainfall after application aids soil penetration. Optimum weed control with Flomide or Engage also requires cooler conditions, so that the propyzamide can penetrates and persist in the top 2 cms of the soil surface. Soil temperatures of 8ºC or less are optimum and we usually reach this some time from mid November onwards. Propyzamide works well at lower temperatures, and, as herbicide degradation in soil is temperature-related, lower cooler temperatures will actually mean longer residual persistence. When it is cold, it takes longer for symptoms to be seen."

David points out that growers may want to consider combining Flomide or Engage with a contact-acting graminicide. "The combination of propyzamide and a fop/dim graminicide often results in surprisingly good control, even if the black-grass is known to be fop/dim resistant. This mix needs careful timing with regard to weed size, but it appears to enhance grass-weed control. A suitable fungicide can be added to this mixture, optimising spray application costs. Both Flomide and Engage are well known genuine high quality propyzamides, manufactured for Interfarm by the primary manufacturer, Dow AgroSciences. For this reason growers can be assured that these herbicides will mix easily, with no problem is the mixing process. They are products of high specification and quality and will deliver consistently excellent levels of control without the risk of crop damage."


"Another aspect to consider when applying propyzamide is crop stage. The label says that propyzamide can be applied from the 1st October onwards when the winter rape crop has three true leaves until the end of January. In winter oilseed rape, crop size is not particularly significant as long as the crop roots are below the herbicide layer. When the crop has three true leaves, the crop’s roots will be well below the herbicide layer and crop selectivity will be good. If the autumn does close in, it is reassuring to know that you have right up to the end of January to tackle weeds in rape," says Dr. Stormonth.

In winter beans application timing for Engage and Flomide is pre-emergence. "This means that propyzamide has a spray window of November or December during the months when this crop is planted and when conditions will be optimal for performance and persistence. With the loss of simazine and trifluralin, propyzamide will play a more significant role in this break crop and will, of course have no problems of resistance," advises David.

Propyzamide is available from Interfarm as Engage (50% WP) and Flomide (400g/L 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. Engage is recommended at 1.4 kg or 1.7 kg/ha and Flomide at 1.7 l/ha or 2.1 l/ha depending on weed species.

For further comment and information, please contact Dr. David Stormonth, Technical Manager, Interfarm UK Ltd. on 01354 741414 or 07818 036506 (mobile) or e-mail david.stormonth@interfarm.co.uk

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