North: Keep up the fight against grassweeds and disease

Crop progress

A period of wetter conditions to the West and North of the region during the first half of March held up field work, but improved weather towards the end of the month has seen activity start again. Leading into April, most farmers are working through list of jobs that includes fertiliser dressing, barley and oilseed rape plant growth regulator (PGR) applications and early fungicides on early-drilled disease susceptible winter wheat crops.

Spring cereal drilling is nearing completion and finishing sugar beet drilling and potato planting is now the focus for April in the North of England.

North of the Humber, oilseed rape crops have generally got away well this spring. With the dry autumn and cabbage stem flea beetle onslaught, there have been a few expectations, with hotspots of the pest in parts of Yorkshire.

Adam's agronomy tips for April

1. Strike final blow to grassweeds in wheat crops

Finishing off grassweed programmes on spring germinating grassweeds such as bromes, wild oats and ryegrasses is top of farmer’s to-do list in April. Having exhausted all cultural control methods available to this point, Monolith (mesosulfuron + propoxycarbazone) would be my recommended product of choice in mixed grassweed situations to tidy up any survivors. Apply onto an actively growing weed with a dry leaf. If concerned about crop effect, use as standalone treatment as soon as possible and return at a later date with any fungicide, PGR and fertiliser applications.

2. Tailor early wheat fungicide applications based on risk

Generally, the further North in the region, the earlier winter wheat is drilled, and these crops are approaching the T0 timing. Recent rainfall has kept disease pressure high and at our local trials site near Cawood, Septoria and yellow rust can be found in untreated susceptible varieties (drilled on 26 September). Further South, winter wheat was sown later due to grassweeds infestations. This, matched with better disease resistant varieties, will mean T0 applications should be recommended on a field-by-field basis, dependant on risk.

If no T0 is planned, timeliness of T1 application in April will be key and prepare to be flexible with product choice and rate. My T1 recommendation in a well-timed scenario would be 1.0L/ha of Ascra (bixafen + fluopyram + prothioconazole) or 1.0L/ha of Aviator (bixafen + prothioconazole) if more concerned about stem-based diseases, plus multi-site.

3. Use SDHI-azole combination at T1 in barley

Winter barley crops in the region are moving quickly, with nitrogen applications on and fungicide and PGR sprays imminent. Mildew remains to be the most common issue in these crops, although I have had a few reports of brown rust also. Ramularia remains the major disease concern in barley, but it is usually a later season disease. My recommendation for T1 applications in April would be Siltra (bixafen + prothioconazole) at 0.6L/ha. The product contains both the best azole and best SDHI (succinate dehydrogenase inhibitors) on key barley diseases.

4. Protect OSR crops from sclerotinia at flowering

Light leaf spot has been easily found using the ADAS SpotCheck service this spring and treated appropriately. Flowers are being now being seen in most oilseed rape fields and with PGR-based stem extension sprays already applied, thoughts in April move to flowering sprays.

Prothioconazole +/- an SDHI at early- to mid-flowering would be my recommendation to protect against sclerotinia and provide a useful light leaf spot top up. Keep an eye on pollen beetle levels, especially in crops infested with cabbage stem flea beetle larvae, as the likely damage to these weaker crops is likely to be more significant. When thresholds are reached, apply appropriate insecticidal control.

5. Maximising cultural and chemical control key to beet virus control

Sugar Beet drilling is well underway in the South of the region. Extra care and due diligence will be needed to manage the risk of virus yellows and soil pest complex following the loss of the neonicotinoid seed dressings last year. Maximising available cultural controls and chemistry will be key.

6. New potato herbicide approved for potatoes

Potato planting is now in full swing in the spud growing areas of Northern England. After last week’s rain, soil conditions are favourable for planting. A new Bayer residual herbicide for potatoes gained approval last week. Emerger (aclonifen) will be a useful addition to weed control programmes this season.