Recent windy, wet weather has meant that spray applications have been limited. With the temperatures dropping and the day length shortening the land no longer dries as quickly and achieving a dry leaf becomes even more difficult. Although the mild November weather has led to good growth and establishment.
If the seed-beds were good the pre-emergence residual herbicides have worked exceptionally well and particularly where tri-allate was used within the programme. However, under the current good growing conditions and in the more difficult blackgrass areas this has required further attention. Residual top-ups and Atlantis (iodosulfuron + mesosulfuron) applications have been applied.
Atlantis efficacy must not be in any way compromised and it is important to monitor the weather and soil temperatures to ensure active weed growth at application. Nozzle choice and water volumes have been discussed and day to day decisions made as to the suitability to spray a small target with a dry leaf. If using a residual to top-up in wheat or barley, ensure the maximum amount of active is not exceeded; for example, 2000g of active for pendimethalin.
Aphid levels have fluctuated week by week, but the general base population is still low. Where possible, insecticides applications are being made to protect against the risk from barley yellow dwarf virus infection. Those that have had Redigo Deter (clothianidin + prothioconazole) dressing will be beginning to run out of persistence and a follow up spray will be planned. Consider manganese applications with this, particularly on land prone to deficiency, to prevent tiller loss.
Similarly in winter oilseed rape where aphids are being found applications have been made against Myzus Persicae, along with fungicides. With resistance widespread in these aphid populations there has been approval for the use of Teppeki (flonicamid) for this autumn alongside existing approvals for Biscaya (thiacloprid) and Plenum (pymetrozine).
Temperatures are slowly dropping enough for propyzamide (Kerb) applications. Fortunately, where an early carbetamide or clethodim application has removed the early germinating blackgrass, this will allow for any delay in Kerb application. Clearly temperatures are dropping and the decision has to be made regarding travelling on increasingly wetter soils. Where poppy, cleaver or mayweed is present Astrokerb (aminopyralid + propyzamide) will be used as the new label for Dow Shield (clopyralid) and Galera (clopyralid + picloram) does not permit applications before 1 March.
Winter beans are emerging well along with both blackgrass and ryegrass, although those who delayed drilling and the delay of the pre-emergence were rewarded with opportunities to spray with glyphosate. Post-emergence carbetamide applications will be planned in bad blackgrass areas.