This month’s update includes information on:
We have had more of a winter this year than the last two or three, which is good news for growers. There hasn’t been days and days of prolonged cold, but temperatures have generally stayed low.
The oilseed rape crop is just starting to move, but with soil temperatures still down at 3-4C and the ground wet, it will be slow for fieldwork to get into full swing. The next priority is getting some nitrogen on and I’d expect those on the lightest land to start in the next week or so.
Light leaf spot is being picked up by the ADAS SpotCheck initiative in my area and the disease is also evident in untreated plots at our trials site. Getting a fungicide on crops as soon as possible is be crucial and fields not treated in the autumn should be prioritised. The rest will still need a top up spray too, as the products are only protectant and autumn treatments have now run out of steam.
Micronutrients are also important at this time of year, so if you are going through with the sprayer for light leaf spot, include some boron and magnesium. This will help load up the plant for stem extension when demand for both is at its highest.
Wheats generally look good, although rooting is not as strong as it should be where later-drilled crops were forced in. In these situations, there is the positive of disease pressure being slightly lower. Septoria is the main disease in September-drilled wheats, with mildew and yellow rust kept at lower levels by the cold weather.
Pre-emergence herbicides have worked well and the cold temperatures will also help with follow-up treatments too. Last season soils stayed warm through the winter and grass-weeds kept growing, so were hard to control with post-emergence sprays. This year we are seeing the opposite, with low soil temperatures checking growth and having smaller plants to target will really help with spring control.
Application timing is crucial for contact herbicides and will be dictated by the weather. Typically, it tends to be the third week of March when active growth begins. Sterile brome is a good indicator – it turns purple in cold winter conditions, but will turn back to green when the weed is actively growing again and indicates the ideal time to apply Monolith (mesosulfuron + propoxycarbazone) or Pacifica (iodosulfuron + mesosulfuron).