Careful management of oilseed rape will be vital this autumn; especially with early-drilled crops which have established very well and are now at six true leaves and beyond.
Where phoma is only just starting to appear, we’ll be getting on with metconazole or tebuconazole in the next week or so to optimise rooting and lateral bud development whilst protecting against infection. Where thresholds have been reached, we’ll employ a more curative fusilazole mix, prioritising any small, backward crops.
At the same time, we’ll be including Nutriphite PGA with the fungicide to give an extra boost to root development, and taking the opportunity to ensure our crops are well-balanced for trace elements – boron, in particular, on light and chalky ground.
We’ll be needing a good bit of propyzamide to tackle large amounts of blackgrass and ryegrass coming through in early sown oilseed rape crops too. But soil temperatures are still way too warm and we’re keen to get a nice bit of frost into the canopies of our forward crops before spraying to open them up sufficiently to get the good soil spray coverage we need. The addition of other graminicides will further improve control. We’ve got all of November and December to play with, so there’s no rush yet.
After the drenching we had a couple of weeks back – 2in or more of rain in places – most of our ground is now drying up well and allowing wheat drilling to crack apace.
In response to the delay, we’re upping seed rates from the 240-290 seeds/sq m (depending on soil type and conditions) of late September to 340-380 seeds/sq m this week and further towards the end of month. This and careful SMART Farm trial-based variety choice will also help boost the competitiveness of our crops against this season’s very vigorous weed growth.
Tacky soils and variable drilling depths following the wet weather also mean we’re being particularly careful with our pre-ems, delaying flufenacet applications until peri-emergence wherever we’re not sure of a consistent 25-30cm of soil covering the seed.
Tight supplies mean we’re prioritising our flufenacet for the worst black-grass infestations and extending its pre-em use where necessary by cutting back slightly on rates and including higher levels of prosulfocarb.
Other options worth considering are CTU (where varieties permit) with lower rate flufenacet, or full rate prosulfocarb plus diflufenican. These alternatives may not be as effective but should be sufficient where grass weed problems are less pressing or variety choice and seed rates ensure the most aggressive crop competition.
While we’re focused on the field work, of course, we mustn’t forget to get our Soil Protection Reviews done. New requirements this year make them more onerous than they’ve been to date. And they need to be completed by the end of December to be sure of meeting our environmental responsibilities – not to mention protecting our single farm payments.