Rain has arrived at last over most/all of the south-west with reports of 15 to 30mm this weekend. It is a huge relief and not a moment too soon. I suspect that wheat yields, on thinner soils in particular, may already have been compromised as tiller die-back has been evident for the last couple of weeks.
Flag leaves are emerging in winter wheat and it is time for T2 fungicides. It is earlier than usual but crops have rushed through the growth stages in response to the dry conditions. Whilst yellow rust has been the “headline” disease over the last few weeks, septoria is, as usual, a major risk to the flag leaf. Despite the dry weather there are high levels of the disease on lower leaves and with crops being much shorter than normal, rain splash from this weekend will have transmitted spores all over the plants.
Mildew is a continuing presence in many crops and in more susceptible varieties a specific mildewicide should be added to the T2 mix.
Poor uptake of magnesium, induced by the drought, can also be corrected at this time.
Ears are emerging in winter barley which should by now have had its T2 fungicide. Disease levels are fairly low at present.
Spring barley is at the stem extension stage and T1 fungicides should be applied soon. Disease levels are low but we can expect to see rhynchosporium developing now. The weekend rain will encourage active weed growth and will aid better weed control.
Both winter and spring beans are in flower and need to be monitored for diseases and pests. Weevil are still hitting crops, in some cases following two insecticide treatments, and aphids are likely to infest crops soon. Chocolate spot has been non-existent up to now but we can expect to see it develop in more humid conditions.
Many winter rape crops have finished flowering and no more treatments are needed. In late crops it’s still worth checking for seed weevil. There have been unusually high numbers in some crops this year. The threshold for spraying is only one per plant. Any spraying should be carried out in the evening when pollinating insects are less likely to be in the crop.