I’m reluctant to grumble too much when fellow Crop Watch contributors from elsewhere report on such dire circumstances. However, I think this strap line from last week’s Crop Watch just about sums up the situation in the east: “A difficult and frustrating autumn as poor weather pushes workloads further behind”.
In the east very little field work has been possible during the last fortnight and my estimate is that about 80% of the planned winter cereal area has been drilled. Not so bad, hey? Except, the most recent drilled crops were often pushed into some ugly seed-beds, wet and cloddy with some seed barely covered. As others have reported, pre-emergence sprays have been delayed until emergence to avoid crop damage (not that we could spray in these wet field conditions anyway!) but these are now urgent as grassweeds begin to emerge.
Slugs are enemy number one! In some wheats after rapeseed populations are extremely high – grain hollowing, under and above ground grazing is even occurring in fields not usually associated with slug damage (on lighter soils and after Linseed and beans,). Ugly, unrolled seed-beds are making the battle for control even harder and now crops that were looking reasonably well are often deteriorating as shredding continues. Opportunities for a good kill with metaldehyde have been few as periods of dry weather have been scarce, perhaps this week will be more settled?
All established and late October/early November emerging cereals should be protected from Barley Yellow Dwarf Virus infection, either by seed treatment or a foliar spray, to prevent build up of any colonies that may have already established in these crops. If conditions remain mild then early September sown crops treated with Deter (clothianidin), now 8 weeks post emergence, should receive a foliar application of cypermethrin to continue protection until the aphid migration ceases. In some instances a pyrethroid can be added to a delayed herbicide, but be cautious if frost is forecast.
Due to delayed drilling and high black-grass dormancy opportunities for autumn sulphonyl urea’s e.g. mesosulfuron + iodosulfuron application (Atlantis) may be fewer this year. However, in forward wheats an autumn application should be considered where blackgrass and sterile brome are the target weeds, particularly where blackgrass populations are “more difficult to control” due to high numbers or more resistance types. Applications should be made at the one to three leaf stage of the weeds whilst they are actively growing. Avoid spraying later in the day when damp conditions may prevent the spray drying on the leaf.
In oilseed rape, phoma infection is now at or close to threshold. Small crops are most vulnerable and all crops should be treated soon. The time for propyzamide (e.g. Kerb Flo) and carbetamide (e.g. Crawler) applications on rapeseed is approaching. Cooler temperatures are forecast and soil temperatures of 10C or below will soon trigger sprays.