Crop Watch: T0 fungicides a must in 2017

Plenty of foliar disease is being seen and Neil Potts, in our first Crop Watch update for 2017, says unless there is a particularly hard frosty spell soon, then T0 fungicides will be essential in most crops this season.

However, Tod Hunnisett says the main conversations taking place are about the first top dressings of nitrogen on oilseed rape and second wheat or wheat after oats.

Looking at soil results, Ryan Hudson says they are showing higher levels of soil nitrogen than in previous years, so rates may need adjusting down. 

See also: Fresh reports of clubroot affecting oilseed rape crops

Similarly, David Martindale warns some restraint will be required with the first doses on oilseed rape crops with very large canopies. 

West: Neil Potts

Matford Arable (Devon)

Neil PottsThe relatively dry and mild winter has led to some fairly strong crop growth and some larger than usual crops.

With high crop density, growth conditions have been ideal for the winter development of several foliar diseases.

Winter wheats are showing levels of septoria that are easy to find without looking too hard, and in some crops, there are also high levels of mildew present.

Winter barley crops are showing signs of mildew, and brown rust, and the distribution of these diseases is dependent on site and variety.

Forward crops of oats have easily detectable levels of crown rust and mildew.

Unless we have a particularly hard frosty spell soon, then T0 fungicides are going to be a must in most crops this season.

Due to the predominantly dry weather, most oilseed rape crops have received their planned fungicides with phoma and light leaf spot largely under control.

Crop canopies, which were looking excessive in early November, have been cut back by a few really sharp frosts in late 2016, and by pigeons, which are having their usual go at this crop.

Pre-emergence herbicides, on the whole, appear to have worked well with little or no grassweed in evidence yet, and only a few cleavers and fumitory having made it through the treatments.

Wild oats on some sites have come through in large numbers and are also large.

These will be best removed from the crop at the earliest opportunity before they become truly competitive.

If the weather continues to hold then winter barley and oilseed rape crops will receive the first nitrogen top dressings within the next week or two.

The forward and well-tillered wheat crops will not need much nitrogen too early this year. It is already looking like lodging could be more of a problem than getting enough tillers in the crop to achieve the desired headcount in June.

North: David Martindale

Arable Alliance (Yorkshire)

David MartindaleWinter has so far been quite kind to crops with December and January being relatively dry and only occasional light frosts limiting crop growth.

Even winter barley crops have a healthy glow whereas usually by now they would be suffering from the winter blues and appear more yellow than green.

For winter cereals, it is a case of assessing the level of success from blackgrass herbicide programmes.

Generally, where the full herbicide plan was applied then control seems good, although blackgrass has a funny habit of destroying such optimism when it appears above the crop in June.

The exceptions are where the seed-beds were too cloddy and/or sown early when seed-beds remained dry for several weeks after drilling, which limited herbicide efficacy.

These areas may need some patches spraying with glyphosate sooner rather than later.

Oilseed crops generally look well and so far pigeon damage has been more limited than usual.

Light leaf spot remains at low levels partially due to a shift to growing more resistant varieties.

Where no autumn fungicide was applied, then phoma levels are exceptionally high in susceptible varieties and some yield penalty is a likely consequence.

Some growers are itching to be applying the first doses of nitrogen to oilseed rape, however, some restraint will be required on those canopies which are still very large.

It is better to hold off applying nitrogen to such large crops, as this is one of the best methods of managing canopy size, structure and ultimately lodging risk.

East: Ryan Hudson

Farmacy (Bedfordshire/Hertfordshire)

Ryan HudsonIt has been quite encouraging to see how well the residual herbicides have performed over the past couple of months.

Due to the dry conditions, residual stacks were split between two applications and despite thinking some areas of fields would have to be sprayed off due to significant levels of blackgrass, there is now a carpet of dead blackgrass in some cases.

Later drilling has also helped with more even crop emergence and lower grassweed pressure. 

There is still blackgrass, but only at the two-leaf stage rather than two tillers plus on the earlier-drilled crops.

Contact grassweed herbicides are to be applied when we can ensure a dry leaf and the plants are actively growing.

However, we should be realistic of the levels of control we can expect from contact herbicides and spray off areas of fields with glyphosate where appropriate.

Cereal crops are quite variable with many crops putting on good growth throughout December and early January.

It has been quite easy to find mildew in barley and some rust and septoria in the early drilled wheats.

There have been multiple briefings on fungicides over the past month and it is encouraging we now have so many options.

Oilseed rape has shown signs of new growth, but pigeons appear to be keeping the crop in check in many places.

As soon as conditions allow, nitrogen is being applied to ensure it is available for crop growth as due to the dry autumn, green leaf area is much lower this year than previous years.

This will be crucial in later-drilled crops with fewer tillers to build the canopy.

Grassweed control appears to be good following propyzamide applications.

However, where crops are open, and grassweeds have been a problem, growers have until the end of the month to apply carbetamide to add additional residual grassweed control and take us through into the early spring when the crop should be more competitive.

Soil mineral nitrogen results have been coming back and, in general, there appears to be slightly higher levels of soil nitrogen, with figures up about 15-20% on the past couple of years due to lower rainfall and more variable yields.

South: Tod Hunnisett

AICC (Sussex)

Tod HunnisetIf ever there has been a year when most of the arable-growing population in the South could have disappeared off to Australia for six weeks then this winter would have been the time.

Going back out on farm after in the new year, it was wonderful to see that nothing needed to be done, because everything had already been finished before Christmas.

I was a bit worried the mild spell at the end of December would mean the slugs would come back, but the cold weather that followed was severe and prolonged enough to prevent that.

Any follow-up residual herbicides had enough moisture to make them work as well as we could have hoped.

The difference in weed control between early drilled and later-drilled crops is quite phenomenal, enough to demonstrate to even the most sceptical that there is a benefit to later drilling.

If only we could guarantee all autumns to be like last year.

The cold weather has shrunk back oilseed rape crops quite successfully, and in most cases charlock has been killed without any chemical intervention.

All crops have shown signs of waking up, and conversations are taking place about first top dressings of nitrogen on OSR and second wheats, or wheats after oats.

The next conversations will be about spring grassweed control (too cold yet but we could be doing them within the next month), growth regulators and disease control.

Medium risk is how I would describe the situation at the moment. I always try to stifle a yawn when the conversation gets round to rust in wheat at this time of year.

Septoria tritici is by far our greatest threat. Manage that well and the rust tends to take care of itself.

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