Don’t lose sight of T0 timing is the warning with plentiful yellow rust this season. How bad that is can be seen by a trip to the Bayer Long Sutton trials site at G H Hoyles Ltd. Farm director David Hoyles noted yellow rust in many crops, including Britannia which has a rating of eight against the disease. “It’s more infected than some of the highly susceptible varieties in the Bayer plots,” he quips.
That pressure is probably a result of highly favourable weather. “It’s only this last week that we’ve had any cold weather otherwise it’s been hovering between 8 – 10 degrees,” adds Mr Hoyles.
For Prime Agriculture director Peter Riley he is concerned about the considerable yellow rust threat in some crops but is equally as worried by Septoria. “Septoria is still the bigger threat and it is vital we don’t compromise control,” he warns.
For that reason he is urging growers to adhere to T0 timing – GS30. “Septoria defence starts with an effective T0 to ensure you reach GS32 in a protective situation. However, any movement in this will only risk the disease becoming established ahead of the T1. Then you have no option to move to an SDHI with high rate of triazole, such as Aviator235Xpro (prothioconazole + bixafen), and possibly consider a strobilurin.”
For growers that have established yellow rust he says act ahead of GS30. “A fast acting triazole will help keep the pressure off. I would suggest it is better to do that than bringing T0’s forward and giving Septoria a window to infect plants,” he concludes.