With a return to cold winds during the day and frosts at night crop development remains very steady. In mid-Suffolk rainfall during the last two weeks has not amounted to much more than half an inch in total although further west into the Cambridge area there has been at least twice as much.
Nevertheless what has fallen has been welcome helping crops to pick up applied nitrogen and turn a healthier deeper green colour at last. Disease pressure has been relatively low although reports of yellow rust (mainly on Oakley and Viscount) keep on filtering through. These have tended to be situations where a T0 was not applied or was applied rather late and yellow rust foci just started to develop.
Recent cool damp conditions will be favouring yellow rust but relatively short intervals between fungicide treatments will help considerably to keep the disease at bay. Flag leaves are just starting to show in the more forward crops with most the leaf two part emerged stage. Flag leaf fungicides are likely to be due around 20th May on average but there will be quite a wide window of flag leaf emergence dates.
Most winter barleys have first awns emerging and will be sprayed this week with the T2 fungicide. Spring barleys have recently had a herbicide plus fungicide combination at T1 timing. There has been a considerable emergence of polygonums in spring barley this year due to the cold winter – the correct choice of sulfonylurea herbicide boosted by the addition of HBN or CMPP will provide good control.
Earlier drilled sugar beet is growing well with decisions on the final broad-leaved weed herbicide being made. Dry conditions have resulted in variable emergence of later drilled crops especially on heavier land and weed emergence has also been affected. Reverting so safer herbicide mixtures has been necessary in some situations where split emergence has occurred.
Winter oilseed rape should have now received its flowering fungicide treatment and in the main this has been about 3 weeks since the green/yellow bud fungicide. The later patchier crops may well come under sclerotinia pressure later if delayed flowering coincides with disease pressure developing in warmer wetter conditions.