Tillage advice: Spring crops are under severe stress
The harsh, cold dry weather up to the end of April restricted crop growth and development and while winter crops had been well advanced at the time this weather has brought crops back to their more normal stage of growth for this time of the year.
The April weather restricted spraying in many cases. There is some evidence of spray damage around the country where spraying took place during this cold period.
However, it is always better to hold off on spraying until there is good growth and no frosts forecast. You can generally be happy in the knowledge that if growth conditions are poor crops are not moving through stages so there is less likelihood of correct timings being missed, which is always a concern. There is also no doubt that spraying crops that are under pressure is likely to lead to more damage.
Weather last week continued to remain cool and very dry and spring crops, in particular, are under severe stress. Last week also provided the first significant evidence of barley yellow dwarf virus (BYDV) in winter crops. I came across serious damage in east Wicklow, which is generally seven to 10 days ahead of growth more inland. The levels of BYDV especially in early-sown crops is significant and worrying. Awns have begun to appear in most winter barley crops.
It is now too late for any further growth regulation. Crops are generally clean and with awns emerging many may be considering the final fungicide. However, with 10 or 11 weeks to go to harvest it is possibly too early to expect this spray to keep this crop clean until then. The more backward crops, if still at flag leaf, could benefit from a growth regulator especially if these crops are strong. The final spray should include a triazole plus a strob with or without a SDHI. Always include chlorothalonil in the mix.
All winter wheat crops should have received their T1 fungicide by now. It is still generally too early for T2s but rust should be monitored in all crops especially down south where there are reports of the disease appearing.
Many winter oat crops were due to get their main growth regulation towards the end of April. In many cases this was postponed due to the weather and from previous experience. It is likely that much of this growth regulation on oats was completed last week during the spell of good weather. If not, and as most winter oat crops are now likely past growth stage 32/33, options for further growth regulation are limited. The new Meddax Max which can be used on winter oats up to growth stage 39 is probably now the last option.
Spring crops are now at the ideal growth stage (15 to 22) for herbicide treatment but spraying should be avoided until growth conditions improve. There is an amazing range of herbicides now available for this task with more new products launched again for this season.