This month’s update includes information on:
It has been a relatively dry and cold winter period in the South East so far and that has meant growth has shut down out in the fields.
I am getting reports of good ground conditions, so as soon as it warms up and crops start to move we need to be on our toes and ready for spring cultivations, spraying and fertiliser applications.
There is more oilseed rape in the ground this year and despite early flea beetle concerns, rain at just the right time helped crops grow away well.
It has been a while since the last fungicide applications in the autumn, so it is time to look out for signs of light leaf spot. This can be done by incubating some leaves and seeing if any latent infection expresses itself or samples tested using the ADAS SpotCheck service. Where you find latent infection, an application of 0.32l/ha of Proline (prothiconazole) as soon as conditions allow will help prevent disease spread.
Pigeons is the next pest problem to solve, particularly in thin or patchy crops. Remember that birds can get used to the various scaring measures, so try and mix things up as much as possible.
Overall, wheats look good and residual herbicides applied in the autumn have done a good job. Growers need to be aware of any fields where grassweeds might have escaped the pre-emergence sprays and think about post-emergence control.
Although contact products such as Monolith (mesosulfuron + propoxycarbazone) and Pacifica (mesosulfuron + iodosulfuron) can be applied from 1 Feb, it is still cold and conditions aren’t quite right yet. Remember grass-weeds need to be at the 2-3 leaf stage and actively growing to get the best control.
In a predominantly grass-weed situation, Monolith is the best option and will give 10% extra control of black-grass over Atlantis (mesosulfuron + iodosulfuron). Where broad-leaved weeds are also the target, Pacifica is a better fit.
The cold and dry weather means disease pressure is relatively low in wheat, but much will depend on the weather from now on. It is worth thinking about risk based on drill date and variety to plan fungicide programmes.
Fungicide resistance in septoria populations is a major concern in both the azole and SDHI groups. For T0 sprays consider dropping azoles and using a multisite on its own where septoria is the main concern. Adding a strobilurin for rust or specific mildewicide for mildew will also help ease pressure on the azole group.
If it is necessary to use an azole at T0, avoid epoxiconazole and prothioconazole, as septoria isolates can be cross-resistant to both actives and early application may compromise efficacy later in the programme. Keep rates up too. Azoles have very different intrinsic activities on septoria, and using the right dose of Prothioconazole is crucial to help protect the SDHIs