Crop stress is evident across the board although earlier drilled autumn crops on heavier land are fairing better. Winter wheats are reacting to the dry conditions and lack of nitrogen uptake by moving rapidly through the growth stages with many flag leaves now emerging or emerged. The final dose of nitrogen has generally been applied although knowing how much to apply has been very diffcult to calculate. Where urea was used in March and April an estimate of nitrogen volatilisation has been made but this has generally been offset by a reduced yield potential.
T2 fungicide decisions are being made in the context of high yellow rust risk across many varieties including some with a 9 rating for the disease which have nevertheless exhibited active yellow rust. Its possible the ‘Claire race’ of yellow rust is the cause but this has not yet been confirmed. This could explain the breakdown of single-gene resistance in Claire and related varieties. In some UAP trials in 2010 yellow rust was responsible for the loss of 30% of yield in Robigus and over 40% of yield in Oakley. Robust fungicide doses of triazole + strobilurin will be needed at T2 where yellow rust is a risk with intervals kept to a maximum of 3 weeks. A top up fungicide at T3 would also be sensible to maintain yellow rust protection. In the few varieties that aren’t breaking down to yellow rust a combined T2/T3 fungicide may well be adequate considering the rapid speed of crop development.
At the time of writing we are expecting rain in the next couple of days – if it arrives management decisions on poorer winter crops and spring crops may be very different. At the moment it is a case of trying to reduce stress on crops by applying foliar nutrients and fungicide where disease is taking advantage of susceptible crops. In the main it is mildew that is putting pressure on cereals. Where pesticides are being applied we are being careful to avoid tank mixing too many products and avoiding spraying during hot conditions. The spring crop that impresses more than any other is sugar beet. Considering the lack of rain most beet crops have established and continued to grow very well although weed control has been challenging. Tight intervals have been required to keep on top of weeds.