The wet weather continues! So far in this area we have had 40 – 55mm of rain in June with more to come. Disease pressure therefore remains high with conditions favouring Septoria tritici, yellow rust and fusarium particularly, but brown rust is also evident despite the weather. With wheat ears fully emerged all crops have either had or are lined up for a T3 fungicide. In milling wheats this will be a minimum half-dose of a fusarium active triazole with additional activity on foliar disease, especially Septoria.
In feed wheats the main focus will be on topping up foliar disease activity. In yellow rust varieties such as Oakley the T3 includes some strobilurin as well where we haven’t already used 2 strobs in the program.
Heavy rainfall, combined with strong winds, have knocked crops about. Winter barleys seem to be worst affected but many oilseed rape crops are now leaning. Much of this seems to be root lodging where wet soils have lost their strength and have not been able to resist the leverage of heavy canopies.
Strategies for managing grassweeds next year are being formulated field-by-field, as surviving grassweed populations are assessed. Cultural control is going to have to feature more and more to offset the risk of the herbicide chemistry performing poorly – as it has this year in many cases. Resistance is only a part of the picture.
In many cases we are going to have to drive down starting populations with whatever it takes before drilling. Ploughing is one approach if done well and as long as it doesn’t result in grassweed seed being ploughed back up from previous years. Stale seedbeds can be very successful if there is sufficient rainfall to germinate a high proportion of weed seed but as this approach is reliant on the weather it is much more of a gamble.
Delaying drilling can have a huge impact on grassweed populations in the right year. We may need to adopt a much more flexible approach meaning that drilling should be delayed until we are confident that a large percentage of the grassweeds have germinated and been sprayed off – this may mean delaying drilling until spring.