June 3, 2020
Talking Agronomy with Jo Bell
We have seldom seen such diverse growth stages across our spring crops, much within individual fields. Especially where we have still had no meaningful rain. I have spring beans 3” tall in some parts of the field and yet to emerge in others – none of which have had any insecticide to date.
Sugar beet herbicide applications are proving a challenge with huge differences in crop stage within fields. Luckily weeds are slow to come too in some cases with the dry. However, fen soils with high weed pressures are a different story, so we have to be careful but brave… no pain no gain!
An additional complication is the need to include Biscaya (thiacloprid) in the mix to deal with an early arrival of aphids, making good use of this spring’s emergency authorisation in the absence of any seed treatment protection.
Gout fly has made a much earlier appearance than usual too. We have already had to spray our 2020-drilled winter wheats. So, it looks like they will need the two-spray programme regularly required for our spring cereals.
Thankfully, Septoria pressure is relatively low further east but, knowing how rapidly things can change if we get the rain many of our crops could really do with, we are keeping-up a strong protective programme through to T2.
While the next generation Septoria chemistry adds some valuable curative activity to our T2 armoury, it is not an input we feel most of our crops will justify this season. All the more so, as it is relatively weak on the rusts that are most definitely our biggest threat.
Instead, T2s will be based around our tried-and-trusted bixafen + prothioconazole co-formulation; fluxapyroxad with epoxiconazole + metconazole where extra Septoria strength is required; and Solatenol with a triazole where we need the strongest defence against yellow and brown rust – all with a multi-site. For extra rust effect we will add a strobilurin if we haven’t used up our permitted number of applications.
As always we need to be both technically and economically correct at T2 to avoid unnecessary follow-ups, particularly with this season’s limited crop potential.
For the best balance here, we are gearing our fungicide programmes carefully to the very latest intelligence on individual variety risks that go well beyond Recommended List ratings.
Key to our decision-making is the Agrii Advisory List which complements the RL with the most up-to-date disease scoring from the comprehensive variety trials run by our research colleagues across the country.
As well as highlighting worrying weaknesses in the rust resistance of many wheats not necessarily apparent in the RL, the Agrii List employs detailed ancestry information to give us the best possible guidance on the disease risk of today’s varieties. Variety sustainability is also being realistically scrutinised with new metrics scores. These will be invaluable in choosing next season’s varieties.
Armed with this extra insight we are particularly alert to wheats with Hereford in their pedigree. And we can see how carefully we need to tread with some new varieties whose family trees are quite scary disease-wise.
In addition to stepping-up our variety specific agronomy with better intelligence on disease and lodging risks, we have been finding the free Rhiza Digital services on offer during the coronavirus restrictions very useful.
In particular, its satellite NDVI imagery supported by the geo-referenced photos we are taking during our field-walking is enabling us to target final wheat nitrogen applications much more precisely to where they will deliver the greatest return.
With all the nitrogen applied on to our spring barley – and waiting for the rain – we are just starting in on their T1s, keeping the programme strong to deal with the Rynchosporium that’s already evident, not to mention the rust and net blotch that are always a risk, even in relatively dry summers.