Possible March work for East Anglian growers

Crop Progress

After being very cold with lots of frosts through a lot of January and early February, towards the end of the month it has started to warm up with some nice sunny days. That’s started to get plants growing again, which is good unless they’re weeds, when it is less nice.

Most East Anglian growers either went early, or delayed drilling with cereal drilling. The early drilled cereals are quite forward with a lot of tillering and biomass. Those that held off, the crops are more like what you’d expect – unassumingly normal.

Some of the oilseed rape crops that survived the dry autumn and flea beetle attacks, were looking quite big before Christmas but have gone backwards since with the frosts, pigeons and flea beetle larvae.

Spring barley drilling has started with decent ground conditions, while fertiliser spreaders have been busy. Overwintered ploughed land has weathered, and crumbled nicely into almost perfect seedbeds for drilling – as long as we don’t get some horrible weather and turn it to mush.

Rachel’s agronomy tips for March

1. Prioritise grassweed control in cereals

Growers who delayed drilling and managed to get pre-emergence herbicides on at the right time are coming into spring with reasonably clean fields. Unfortunately, grassweed control is not so great for growers that drilled earlier or where weather stopped applications of residual herbicides.

With weather improving that’s leading to thinking about trying to get on top of grassweeds while they are still small – you’re likely to get better control when applying the chemical onto a younger, smaller plant.

At the moment, it doesn’t appear many growers are considering getting rid of the crop entirely, although maybe that’s more to do with current grain prices. 

The key for spring grassweed control is making sure plants are growing enough to take up the chemical. With the cold nights in February that may not have been the case.

Product options include Pacifica Plus (mesosulfuron + iodosulfuron + amidosulfuron) and Atlantis Star (mesosulfuron + iodosulfuron + thiencarbazone). Atlantis Star contains 15g/ha of mesosulfuron at the full label rate of 0.33 kg/ha, and if you’re targeting bromes from 1 March, you can get the same amount of mesosulfuron with Pacifica Plus.

Whatever choice you make, concentrate on application technique to maximise efficacy – looking at nozzle choice, droplet size and boom heights to make sure you get as much chemical as possible onto a small target.

With spring barley already well underway, remember that Liberator (flufenacet + diflufenican) now has an on-label approval for pre-emergence grassweed control, which can be quite useful if you want to have some residual activity in the crop.

2. Continue monitoring for light leaf spot

I’ve used our free Spotcheck service for oilseed rape diseases on a couple of farms, and it is about at various levels. With warmer weather it will likely start to cycle more quickly.

Spotcheck is still available until the end of March to use if you want to see what disease levels in your crop. Those crops which were either treated only in autumn or not at all, or those with a higher varietal susceptibility will be most at risk.

If you are starting to find light leaf spot in the crop then it is likely worth getting on top of it now, rather than waiting for flowering. A good option at this time of year will be Proline (prothioconazole), and adding some tebuconazole if you need some additional activity or growth regulatory activity.

3. Assess disease pressure in winter barley

Understanding what the disease weaknesses of the varieties you have in the ground will help target and prioritise field walking during March.

Winter barley yield comes from maximising the numbers of ears / sqm and therefore tiller retention at this time of year is crucial, with uncontrolled disease likely to lead to tiller abortion.

If you have active mildew and Rhynchosporium that requires a T0 spray during March, then cyprodinil or prothioconazole are options you could consider.

Towards the end of the month, and into April, the most important fungicide spray of the season will be due around GS30/31. Both Ascra (bixafen + fluopyram + prothioconaozle) and Siltra (bixafen + prothioconazole) could be used for this timing.

Remember you can only use Ascra once in a barley crop, and it probably depends on what diseases you are most worried about. If it’s Ramularia then you could save it for T2 and use Siltra at T1; if it’s more general foliar diseases like net blotch and Rhynchosporium then using your best product at the most important timing makes sense.

4. Target yellow rust susceptibility for wheat T0 sprays

The same applies in winter wheat as in winter barley – look at varietal disease resistance ratings, especially yellow rust, for your crops to help you target which might be at most risk.

But don’t forget to check all varieties as you can never be sure when a variety’s resistance may break down. The AHDB Recommended List this year also has information on juvenile yellow rust plant resistance, which can be useful as not all varieties are resistant as both young and adult plants.

Where you are finding yellow rust or there is a varietal risk, using a yellow rust active fungicide at T0, such as tebuconazole or a strobilurin, could be useful to help break the disease cycle and buy time if T1 sprays are delayed by weather.

If you do use tebuconazole, remember it shouldn’t be mixed with a mesosulfuron-containing product for crop safety reasons.

5. Remember stewardship advice if using Conviso sugar beet

Both the number and area of Conviso Smart sugar beet varieties continues to grow after very positive responses to its use in recent seasons.

If you are growing, especially for the first time, please do follow the stewardship guidelines in place for the system to reduce the risk of resistance developing. These include strict bolter management, which starts with carefully assessing drilling date to minimise risk.

An obvious precaution needed is to make sure you know which fields you have drilled with Conviso varieties, especially if you also have conventional varieties on farm, and not to drill fields with both. The last thing you want is to spray the Conviso One (foramsulfuron + thiencarbazone) herbicide on a susceptible variety.

6. Get the sprayer ready

March is the start of the season when the sprayer will be most in demand, and it could have been sat in the shed over winter. Before starting any of the jobs this spring be sure to give it a good check over and do any maintenance required. You don’t want to be in the middle of the field and finding you have a problem.