Recent unsettled weather has slowed progress; however, the amount of outstanding drilling (mainly after roots) and spraying feels manageable given a few days of good weather.
Emerged cereal crops look well and early- to mid-September sown crops are well tillered. Barley yellow dwarf virus (BYDV) and aphid control should be reviewed on a field-by-field basis. It is worth noting that the Rothamsted Aphid Bulletin shows active migration of the Bird Cherry Aphid (primary BYDV vector) at the end of October. Now is the time to consider a final insecticide for BYDV control to any unprotected crops. Deter (clothianidin) treated crops which emerged in mid- to late-September will be protected for six weeks after emergence, some of these may need a foliar top up of insecticide now if conditions remain mild.
Low blackgrass dormancy and good growing conditions have caused grass weeds to emerge quickly. Some September and early October drilled crops already have high blackgrass populations, many at the two leaf or early tillering stage. Where pre-emergence residuals have been stacked emerging black-grass populations tend to be lower, looking tired and affected. However, where residuals were delayed until full crop emergence control is often disappointing.
Where black-grass populations are easy to find an autumn application of sulfonylurea’s e.g. Atlantis (iodosulfuron + mesosulfuron) or Unite (flupyrsulfuron + pyroxsulam), usually with an appropriate residual been recommended. Atlantis applications must be applied at a time that enables the spray to dry on the leaf before the evening dew settles; at this time of year these opportunities can be rare! In marginal conditions or where resistance could be an issue good spray techniques are paramount.
Another application to consider (if not already done) is foliar manganese nutrition to improve winter hardiness of crops on soils prone to deficiency (light, organic and puffy). Many untreated crops are already showing clear deficiency symptoms.
Mild conditions in late October have delayed the onset of propyzamide (e.g. Kerb Flo) and carbetamide (e.g. Crawler), however, cooler conditions and soil temperatures of 10C and falling will soon trigger applications. These actives also work best when soils are moist, allowing the actives to be held in the top few centimetres of soil where weeds are germinating. However, applications should follow stewardship guidelines to minimise run off into surface water, in particular applications before rainfall to soils at field capacity should be avoided. During October, phoma infection has developed slowly, if necessary this application can be combined with any outstanding phoma control.