Four possible jobs for southern growers in February

Crop Progress

Most cereal crops look decent as we head into February, although there were some waterlogged or flooded fields in January in some lower lying areas.

The cold snap before Christmas will have helped suppress some of the disease which was bubbling away. Mildew has been the most prevalent disease issue in cereals.

Winter barley went in early and was lush so sheep have been used in some cases to provide some natural growth regulation.

Those oilseed rape that survived a tricky establishment period are also looking half decent now. A few crops hit thresholds for Phoma, but light leaf spot levels have been low so far.

Matt’s agronomy tips for February

1. Take early weed control opportunities

If temperatures start to rise, then there might be an early opportunity to take out any grass weeds that have come through an autumn residual spray. The weeds need to be growing for best efficacy from contact herbicides. A good indicator for that is whether your lawn is growing – if it is you can bet grass weeds in cereal crops will be too.

With favourable conditions, applications in February can be a good time to get on as any weeds that have come through the winter are likely to be at a size where herbicides will still be effective. Leaving sprays until March or even April can allow those weeds to get too large or be going through stem extension which is detrimental for good control. Going as early as conditions allow is likely to be best for efficacy.

In the southwest bromes and ryegrass are more likely to be the target difficult weeds. Walking fields to pinpoint areas or whole fields that will need attention is also worthwhile in February even if the weather doesn’t play ball for a herbicide application.

It’s also worth considering whether resistance tests are representative of the whole field or just a difficult patch within the field. Our Italian Ryegrass Survey suggests the farm wide population often does not have the same resistance status as the bad patch where a resistance test sampling was undertaken. So you might think your mesosulfuron-containing product will no longer be effective across the whole farm, but in reality it’s just a patch in the field that has proven difficult to control, and the product is still helping across large areas.

Where conditions are suitable for spraying, there is a choice between Pacifica Plus (mesosulfuron + iodosulfuron + amidosulfuron) and newly launched Atlantis Star (mesosulfuron + iodosulfuron + thiencarbazone).

At the label rate of 0.33 kg/ha Atlantis Star delivers a higher rate (15g/ha) of mesosulfuron than the maximum permitted dose in February (0.4 kg/ha) of Pacifica Plus, which delivers 12g/ha of mesosulfuron. Thiencarbazone enhances activity against difficult grassweeds, as well controlling a decent range of broadleaf weeds.

So if you’re targeting bromes, ryegrass or black-grass I would consider using Atlantis Star  in February to take advantage of being able to go early with that higher dose.

2. Use Spotcheck to monitor for oilseed rape diseases

While levels of light leaf spot so far have been low, it’s worth continuing to monitor for the disease in February as it often starts to become more of an issue after Christmas. Using our free Spotcheck service means you can get leaves checked for disease by the experts at ADAS through February and March.

The incubation test can help identify light leaf spot that is in the leaves but not yet visually apparent and help you decide whether to spray.

If a spray is needed, Proline (prothiconazole) gives long lasting protection against light leaf spot and Phoma without any growth regulatory effect. If you also need the latter, use a prothioconazole + tebuconazole co-formulation.

3. Finish off cover crop destruction

Many cover crops will have been grazed, rolled in December frosts or had a first application of glyphosate applied already, but it’s worth checking the effectiveness of those techniques and whether an application of glyphosate to finish off any remaining biomass is needed pre-drilling of spring crops.

If there was a decent amount of biomass originally there might have been shading of the lower canopy that will need a second application, while rolling on the frost or grazing might not have killed off every species.

Ideally time any last applications of glyphosate around a month before target drilling dates to leave the seedbed most conducive for drilling. Large biomass cover crops, in particular, can create anaerobic conditions in the soil if there is rapid mass root decomposition or, in dry springs, contribute to losing moisture from seedbeds, compromising spring crop establishment. Generally earlier applications help mitigate these risks.

There are no hard and fast rules on glyphosate rates, but continue to target rates to the most difficult cover crop species to take out and match to weed size.

4. Identify nematode risk in potato fields

Any last soil samples for potato cyst and free-living nematode risk should be taken in February in potato fields. These will help identify risk in the coming season’s fields and then help formulate plans for control.

Depending on the test results this could include the use of Velum Prime (fluopyram) in conjunction with a granular nematicide. Velum Prime is a liquid formulation of the SDHI F fluopyram, which is highly active in protecting potato crops from plant parasitic nematodes.

It works by inhibiting adenosine triphosphate (ATP) production in mitochondria, causing paralysis then death of juvenile nematodes. Trials have shown effective suppression of both PCN and free-living nematodes from Velum Prime.

If you would like more information on Velum Prime and how to use it, please contact me.