Warming air and soil temperatures alongside extending day length have prompted crop growth and development. Growers have responded by starting nitrogen & sulphur applications to oilseed rape, barley and “less forward” wheats. Nitrogen applications to more forward wheats should be delayed until mid-March to help manipulate tiller numbers and reduce lodging risk.
The first spring pesticide applications are under way. These include spring weed control in OSR for thistles, mayweed and cleavers with a clopyralid-based sprays such as Galera (clopyralid + picloram). To avoid crop injury these applications should be completed before buds are raised above the canopy.
Spring post-emergence grass weed applications such as Atlantis (mesosulfuron+iodosulfuron) and Broadway products (pyroxsulam-based) can be applied when crops are actively growing. Overwintered grasses should be targeted while they are relatively small and soil conditions are moist.
To maximise the efficacy of spring grassweed control follow the manufactures guidelines, paying particular attention to spray quality and when control is difficult avoid tank mixing.
In cereals symptoms of manganese deficiency are widespread after the frosty weather. Puffy soils should be rolled before stem extension and generous doses of manganese applied to correct deficiencies as soon as possible.
Recent cold weather has briefly slowed rust development until temperatures rise. Very susceptible yellow rust varieties such as Oakley without a specific seed dressing for rust control may benefit from a low dose of appropriate triazole, to stall disease progression until T0. Growers should avoid pulling the planned T0 too far forward as this could lead to a stretch between fungicide timings later in the programme. T0 is usually applied in mid-March at the start of stem extension.
Wheat bulb fly risk is somewhat lower this season compared with spring 2011. “At risk” crops should be monitored carefully for wheat bulb fly damage. Rolling, early nitrogen and dead heart sprays can be used to reduce the impact of this pest.
Growers should consider spraying off weed growth on overwintered ploughing prior to spring drilling. Sugar beet drilling is likely to start this week; growers should consider the benefits of a pre-emergence herbicide containing chloridizon.