Torrential rain yesterday and already we have had 53mm of rain in May. Little spraying has been done for at least two weeks, except by growers that have been prepared to grab every opportunity and have got a surprising amount treated.
The wet brings with it lots of disease potential; septoria in wheat, rhynchosporium and net blotch in barley, sclerotinia in rape and chocolate spot in beans. They all need to be catered for.
Forward crops of winter wheat have the flag leaf showing and in some cases still have not had a T1 fungicide. These crops now need a very effective septoria eradicant as the risk of severe septoria is very high. Growers will just have to make ruts and splash through the puddles to get the products applied.
With the flag leaf emerging,T2 will be due soon. This should go on at the normal timing even where T1 has been delayed. Yellow rust has been well controlled by T1′s but there is still the potential for it to explode back into life as the fungicidal effect runs out. Septoria though is the number one threat.There should be no thought of stretching the gap, waiting for the ear to emerge and applying one dose to cover both flag leaf and ear.
Choice has to be made between the traditional fungicides and the new SDHI’s. The latter cost more but on a good crop of high yield potential are worth the extra expenditure.
Most crops of winter barley have the flag leaves emerged and a T2 fungicide is essential to protect against rhynchosporium and net blotch, both of which are favoured by wet conditions.
Likewise sclerotinia in oilseed rape. Crops should have had a fungicide at early petal fall but if that is now more than three weeks ago, a follow-up treatment should be applied to see the crop through to harvest. So far this year, weevil numbers are very low so there should be no need for insecticides at this stage. If you do need to apply one please remember the bees and choose and use products accordingly.
Weevil are, however, a major problem in spring beans; keep monitoring crops and spray if leaf damage is still occurring. Winter beans are in flower and chocolate spot is a potential threat; although the temperatures are at present too low for the disease to really take off , treatments are aimed at prevention not cure.