I am still struggling to tidy up outstanding jobs left over from the autumn and a combination of ground conditions and lack of suitable spray days continues to thwart progress.
Late-drilled crops still needing residual herbicides will soon start to coincide with the earlier-drilled fields, where attention to grass-weeds is becoming a priority. Some of these are getting pretty big now, particularly rye-grass and the brome species.
There will always be a delicate compromise between weed size and the need for sufficient temperature to allow good chemical uptake and efficacy. For me, slightly earlier applications nearly always deliver a strong result, with later timings on bigger weeds prone to being less successful, and such failures remain in view for the rest of the season. Most unsatisfactory for all concerned.
T0 timing is rapidly approaching and decisions are being fine-tuned. A greater use of multi-site protectants is key to the early success of any programme. Current septoria levels are every bit as severe as previous bad years, but the burning question is when should first sprays go on? Where rust is an issue, there is no dispute about the value of a pre-T0 spray, but with septoria the situation is far from clear cut.
Do we need to protect final leaf 5, which is what would happen with an extra, early treatment. It might make everyone feel better but in terms of tangible yield benefit…I somehow doubt whether it will deliver. I will stick with the more traditional timing aiming to cover leaf 4, and I shall be including a triazole, but not the same active ingredients which I will be relying on at T1 and T2.
First nitrogen doses have kick-started the rape crops into gear and stem extension is now clearly under way. Growth regulation and adapting canopy architecture for maximum yield needs to be sorted now. We understand the physiology of this crop far better now and with the advent of new chemistry it has become much easier to manipulate, providing the other key parameters of plant population and N timing are looked after.
I favour a two-pronged approach; a fungicide with some PGR activity to get early height reduction and a slightly later follow up of a specific growth regulator to create an open well branched canopy which allows good penetration of sunlight. Just remember lodged crops don’t yield well and check the varieties you think have been drilled are correct – semi dwarfs have a different PGR requirement to tall, leggy vigorous hybrids.
Spring drilling is progressing well. Spring beans were the first to leave the bag and my acreage of these, and other pulses, has risen considerably. As such, I am sure there will be a shortfall of appropriate products which may cause some grief, but time will tell. They provide a wonderful entry for wheat, but only if harvest doesn’t get pushed too late. Disease control programmes need to be robust and early; crops carrying too much green leaf in early September come late to the combine, and can fall victim to the vagaries of autumnal weather. Strong pre-emergence weed control is a must, with an over reliance on a post-em top up treatments often ending in tears. Desiccation, preferably with diquat, gets the beans in the barn quicker, drier and cleaner.
Neil Buchanan is an Agrovista agronomist based in Shropshire. He advises clients across the West Midlands, growing cereals, oilseed rape, pulses and potatoes.