The rise in temperatures this week will create disease pressure on crops. Rhynchosporium (rhyncho) has been seen in some winter barley crops already.
Depending on the part of the country you’re in, crops may be more forward than others and pressure may be greater.
Taking these factors and variety choice into account, farmers may try and push out the first spray timing. However, prevention is always better than cure, so don’t wait until rhyncho is rampant across fields to spray.
However, where disease pressure is low and the T1 is applied late, a two-spray programme may be implemented in some areas. The number of sprays applied will also depend on how quickly crops will grow as temperatures increase.
Two-spray programmes are impractical in high disease pressure areas, particularly in the south of the country.
Rhynchosporium visible on a winter barley crop
Farmers should be keeping an eye on disease levels and, where disease is present on winter barley, a T1 spray should be applied as soon as possible.
T1 options
T1 options should include prothioconazole and a strob. Where net blotch is a threat, a strob should be added. Mildewcide should be applied where the disease can be seen.
Some farmers may opt for an SDHI and a triazole at this timing. SDHI products are a good option for crops which will not receive a T1 spray immediately or may not receive it until towards the end of the month.
Know your variety
It is important to know your variety. Look out for the diseases that varieties are most prone to. For example, KWS Cassia has a low resistance to rhyncho and KWS Tower has a low resistance to net blotch.
Source: Department of Agriculture, Food and the Marine