East: Delay winter wheat drilling for better blackgrass control

Just like at Cereals, blackgrass control is being widely discussed on farm at the moment and, if you learn anything from last year to take forward to this coming autumn, it’s that delaying the drilling of the winter wheat crop is clearly up there as being an extremely important detail.

Even where all available pre-emergence herbicides were stacked and timed to perfection with no expense being spared, if the crop was in the ground before that second flush of blackgrass had been dealt with prior to drilling – around the 25 October – the blackgrass has won again. My advice for this coming autumn is where you have bad blackgrass and you are intent upon putting winter wheat in the ground, you must hold your nerve and leave the drill in the shed until the end of October – the difference between good blackgrass control and bad blackgrass control was five days!

Winter wheat spraying is now largely complete, with the last of the T3 fungicides being applied at the end of last week. Having spent around £95/Ha in total on my four-spray fungicide programme and having used the allowed two strobilurins and two SDHI’s within that programme, I am comfortable that we haven’t spent too much money on achieving spotlessly clean crops from the flag down to leaf five.

The T3 was timed as well as possible just as the first anthers appeared – luckily before the rains came last weekend. We can do no more to control Fusarium ear blight (FEB) and have to accept, that even in perfect conditions, if it turns into a fusarium season, we will only have achieved a maximum of 50% control, even with a robust dose of one of the top three FEB actives. With little need for a foliar disease top up, we concentrated on getting the timing right against FEB – and continue to keep our fingers crossed.

I have yet to find treatable numbers of aphids in wheat – milling or otherwise – but have just in the last 48 hours started to find the odd orange wheat blossom midge (OWBM) stuck in sticky traps and cobwebs around the fields. This is my 11th consecutive season where OWBM control in winter wheat has been unnecessary and now the wheats are in ear and have flowered, that particular risk has passed – but spring wheat crops may still be at risk, so vigilance is still required (1 Midge per 6 ears in seed & milling crops and 1 Midge per 3 ears in feed crops, 3* low drift nozzles, 20 m buffer zones around the outsides), but only spray if necessary – those routine “it only costs a few quid” applications for this pest are ill-advised and unwise – as much from the damage it does to our industry, as the damage it does to our beneficial insects.

Winter barley is all done and dusted and looking similarly clean from top to bottom; spring barley T2s were applied last week – done and dusted and looking clean from top to bottom – in terms of disease anyway, blackgrass seems to be under control where it was an issue, but once the barley opens up we may yet see areas which need the help of a little glyphosate; spring wheat T2 is now largely complete and once again they are looking clean and free of disease from top to bottom – the blackgrass control is far less assured in this crop however, despite our best efforts we may also have to get the glyphosate out for the worst areas with spring wheat being far less competitive than spring barley in the main.

The exception to this is Bellepi drilled this spring which is very clearly “out blackgrassing” the blackgrass with its extraordinarily thick canopy, hopefully it will yield well and then our faith in it will have been well-placed – the Bellepi that was drilled last November is showing similarly high levels of crop canopy competition – we need all the help we can get when it comes to blackgrass control.

Leaf miner has begun to appear in sugar beet crops across Lincolnshire – more widespread in the South, but also relatively easy to find further north. The threshold for treatment is when the number of eggs plus larvae per plant, should be equal to or greater than the square of the number of leaves. Put simply, if you have 4 leaves you need 16 eggs and larvae to justify treatment. Leaf miner burrow between the leaf layers of leaves and the damage looks dramatic, but it’s far more significant in a young crop than it is in the 12 leaf crops that we’re looking at the moment – which incidentally would require 144 eggs and larvae per plant to warrant treatment! The options available are limited and at best unreliable, with lambda cyhalothrin needing to be applied at the instant the eggs hatch because it only kills the grubs as they leave the egg. Speak to your agronomist or sugar beet fieldsman, because it often looks a lot worse than it is.

Conditions are perfect for potato blight at the moment, so blight programmes are well and truly underway, with seven day intervals being maintained. Myzus persicae are beginning to appear in many canopies now and are being closely monitored.

Spring beans are in full flower, with around 20% of pods set now and in the more susceptible varieties, downy mildew is widespread – remarkable considering the humid and thundery weather conditions. The incidence of downy mildew has been patchy, but has been dealt with where necessary. Colonies of black bean aphids suddenly appeared in many fields at the beginning of last week along with bruchid beetle, so suitable insecticides are being included with fungicide applications where necessary, with very early morning applications being made because of the high numbers of bees in the canopies.

Hopefully that light at the end of the tunnel isn’t a freight train heading straight for me!


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