North: Spotlight on disease control in OSR


Now that “Super September” is over we have moved into a more seasonal October with a mix of wet and windy weather. However, both air and soil temperatures have remained unseasonably high. This has implications for applications of propyzamide or carbetamide. Remember that soils need to be at a maximum of 8°C and dropping otherwise efficacy will fall off fairly quickly. Also be aware that both products have water quality issues and product stewardship guidelines must be observed with regard to slopes, rainfall, sub soiling, watercourses.

In general, most crops are looking well. The recent damp weather has improved emergence in drier, cloddy seedbeds. There has been some slug damage but little sign of flea beetle in oilseed rape. We’ve seen some aphid activity but spraying to minimise BYDV should only be undertaken if colonies of aphids are found in a crop.

Oilseed rape crops have established well and our thoughts should now be turning to autumn disease control. In this part of the world light leaf spot is the main issue. Whilst you want to wait as long as possible to cover the main infection period do not delay until the weather prevents a back end spray.  A three quarter dose of a prothioconazole/tebuconazole co-formulation gives the best of both worlds – efficient disease control and a degree of growth regulation.

Winter barley crops are rowed up nicely and winter wheats are coming through with fields still being drilled after potatoes. Weed control tactics will revolve around mixtures of some of the following – pendimethalin, flufenacet, diflufenican and possibly flupyrsulfuron.

There are a couple of “newcomers on the block” – Cyclops (bromoxynil + diflufenican) which should fill the slot vacated by Pixie and Tower (chlorotoluron + diflufenican + pendimethalin) which sees the reintroduction of CTU at a lower rate. Latest date for use of Tower for this year is end of October so by the time you read this it will almost be too late!

Potato lifting has continued apace with the ground conditions favouring minimum tuber damage. Great care will need to be taken with storage, as perfection will be the only standard for movement this season.



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