South: Oilseed rape crops quickly hit full flower

Another warm, dry week in the South East now means apart from maize, all spring drilling is nearing completion. Oilseed rape crops have rapidly moved into full flowering, allowing them to keep ahead of ever increasing pollen beetle activity. With concerns for resistance to pyrethroids where pollen beetle are a concern on more backward and variable crops, alternative insecticide options have been; Rumo (indoxacarb), Plenum (pymetrozine) or Biscaya (thiacloprid). Where not already applied, protectant fungicides for sclerontinia control in oilseed rape are now a priority.

Early sown wheat crops are rapidly moving towards GS32 and leaf three emerging, so T1s are now imminent. Winter barley has now received its T1, which has been based around Cello (prothiconazole + spiromamine + tebuconazole) plus Mobius (trifloxtstrobin + prothiconazole). Fungicide programmes for wheat which shows good yield potential are being based a combination of a triazole, stobilurin and SDHI partner such as Kingdom (boscalid + epoxiconazole) and Curator (asoxystrobin + chlorothalonil) to take account of good disease resistance management and to maximise yield.

Spring pulses are all emerging well, with pea and bean weevil now actively notching leaves. However there is no value in treating crops before they have a worthwhile leaf area to intercept an insecticide.

With a growing awareness of maintaining good soil health and a soil that is biologically active, one consideration that could influence our fungicide programme is the effect an individual active ingredients has on soil bacteria and fungi. At a recent Association of Applied Biologists (AAB) conference, Matthew Shepherd from Natural England talked about their work in measuring a wide range of soil variables, including how they are exploring DNA metabarcoding of soil biology for 40 nature reserves across the UK.

While it is early days for this work when combined with data from productive farmland, it could be possible to begin looking at what levels of active soil biology we have, how our management affects these and is there a link to yield? Can we then find ways to utilise this knowledge to guide how to overcome the yield plateau we are currently experiencing, or just grow crops more efficiently?

With maize drilling now due to start in earnest this week, a little rain would be more than welcome to help its establishment. Trial work also clearly shows the benefit of a starter fertiliser such as Umostart (phosphate + zinc) or DAP placed with the seed to aid early plant development. While rain will also help maintain the potential that all crops are currently showing.

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