East: Septoria and yellow rust start to threaten

As April sweeps in – doesn’t seem 12 months since I said that last time – improving soil temperatures are releasing mineralised nitrogen and finally greening up the more bronzed cereal fields across the county.

First applications of nitrogen have been completed but, along with the welcome increasing soil (currently 7.8C at 10cm) and warmer ambient temperatures comes increasing disease pressure – particularly where recent heavy downpours have occurred, therefore septoria and yellow rust are beginning to threaten.

Leaf four is emerging widely – not just in the more forward pieces – so T0 fungicides are now being  applied. Some have chosen the usual route of triazole plus chlorothalonil, I and many others have chosen strobilurin plus chlorothalonil – both are capable of controlling and protecting against rust and septoria – but whichever route has been taken, the chlorothalonil will once again be the critical part of the mixture – protecting the new growth against septoria spread in these early stages is vital. I’m reluctant to employ a growth regulator split this season because looking at tiller numbers, I really don’t need any more!

Leaf emergence is now governed by phyllochron – accumulated day degrees – so getting out there with a sharp knife and looking inside plants is the only accurate way to determine growth stage. However, some agronomists – and I use the term loosely – out there are extraordinarily talented and are able to assess growth stage from the car seat by simply referring to the calendar . . . unbelievable Jeff!

Blackgrass levels where we managed a couple of flushes of blackgrass from stale seed-beds, where we delayed drilling until the latter parts of October and where we managed to stack the pre-emergence herbicides within three days of drilling, are as low as I have seen them for a number of years. That doesn’t mean we won’t get a spring flush, but it does mean that with thick, healthy, well tillered forward crops, we stand more of a chance of being in control of it rather than it being in control of us – and with prices where they are, at least we might save some money on Atlantis.

Post-emergence blackgrass “control” in winter barley is always difficult to say the least – but full rate Axial (pinoxaden) is your only hope, so make sure you apply it in warm weather and good growing conditions for the best results – but be prepared to be disappointed.

Oilseed rape is well into stem extension and the buds are extending above the canopy in many fields. Light leaf spot sprays have been on for around three weeks due to a sudden increase in levels in early March, but as we can only protect against LLS  – it should be the main driver of  fungicide choice for green/yellow bud applications. Disease should always take priority and plant growth regulation – while important – should not be prioritised at the expense of disease control.

Choose  your weapon wisely. I know we have specific new plant growth regulators (PGRs) in rape, but following crop restrictions and not to mention the price of them, means that detailed cost analysis and heated discussions are called for. With metconazole and tebuconazole more than capable of doing the job of PGRs and forecast harvest prices where they are – it may well be that this is the season to stick with them.

Clethodim damage appears widespread, despite us sticking to the new application guidelines, but it does seem to have done a good job on the blackgrass so, compared to the alternative, I think I can put up with a little damage – damage which incidentally last year apparently did not translate into yield effects.

Pollen beetle is as yet absent as far as I can see, but that hasn’t stopped a certain element in our industry from including insecticides with the fungicides they’ve applied over the last three weeks. We have pollen beetle thresholds for a reason and irresponsible and unnecessary insecticide applications does far more harm than good – not only to non-target predators and beneficials, but also to our industry image – these people should be named and shamed – mind you, the inclusion of an insecticide is beneficial to sales turnover figures!

Spring barley, spring wheat, spring beans, combining peas and linseed are all going in the ground as we speak and, I might say, into some pretty good seed-beds – well, in the top 3in at least – because when you get much deeper than that, it’s still comparable to plasticine despite only 2.5in of rain since the beginning of the year.

Pre-emergence applications of Avadex Excel (cereals, sugar beet, linseed, beans), Liberator (spring cereals apart from spring wheat), Crystal, Defy etc where blackgrass is an issue will prove  to be vital this season and, whether it be on or off label approval, they should be employed without question – just make sure you have downloaded and hold the relevant Extension of Authorisation for Minor Use (EAMU). The earlier drilled spring barley is now through the ground at two leaves and, with spring upon us, barley yellow dwarf virus (BYDV) vectors will now need careful monitoring.

Sugar beet drilling is going well, at least on the farms who are sticking with the crop. Where blackgrass is a problem, Avadex will be part of the pre-drilling programme, and the inclusion of ethofumesate with the pre-emergence herbicide does make a difference, but check the label to make sure the ethofumesate you are using is cleared for pre-emergence use. Also, as a result of label changes, remember that new label chloridazon (Takron) can only be applied pre-emergence.

There’s a lot of potential out there in the field . . . but  then we’ve said that before!

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