South: Phoma reappears in OSR crops

Early-sown wheats and those on fertile soils have started to wake up and they must be picking up nitrogen from somewhere as they are all a healthy green colour. The warmer conditions following a cold December have stimulated a flush of broad-leaved weeds, nothing too serious, but I haven’t seen any spring-germinated blackgrass yet.


Second wheats and later-drilled crops will get their first sulphur/nitrogen dressing as ground conditions allow but the more forward crops probably won’t need anything until March.


If the crops, and therefore weeds, continue to grow then it’ is worth considering any outstanding Atlantis (iodosulfuron + mesosulfuron) treatments, provided the partner products are within timing limits. If the target weeds are actively growing at the time of application it won’t matter if it comes back cold again afterwards, but don’t spray Atlantis during cold periods.

The high levels of phoma seen in winter oilseed rape last autumn were well controlled by the autumn fungicides and held at bay by the cold weather, but the disease has reappeared in more infected crops this month. Given the severity of the outbreak and the potential value of the crop, a follow-up spray is considered worthwhile in many situations. Most oilseed rape will be getting its first nitrogen with sulphur over the next two weeks.


Some spring barley has gone in on lighter soils in kinder sites. But I’d rather wait a bit before thinking about drilling spring beans or peas as there’s possibly still a lot of wintry weather yet to come. Whatever happens, don’t drill your peas or beans unless you know you are going to be able to get the pre-emergence sprays on. Post-emergence broad-leaved weed control in these crops is a nightmare.

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