| |
Varietal Considerations Essential at T1 timing in Wheat
Date added: 28/04/09 |
A broad-spectrum fungicide based on a triazole applied at a robust rate is what is required at T1 timing, but growers should also take disease susceptibility into account when deciding on what to apply, according to ProCam Group Agronomist Nick Myers.
The function of a T1 spray is to protect the top 3 leaves from foliar diseases such as Septoria, rusts, mildew and to protect the whole plant from stem-based diseases such as eyespot, Fusarium and take-all, he explains.
With Septoria tritici being the main disease at this and T2 timing, growers of varieties such as Claire, Consort, Gallant, Xi19, Einstein, Solstice, Gladiator, Malacca, Hereward, Cordiale and Oakley to make sure they apply a robust T1 treatment in time to fully protect Leaf 3, he warns.
“This year these susceptible varieties, all of which have a disease rating of 5 or less, make up close to 60% of the total wheat area planted.
“This year we are already seeing particular diseases such as yellow rusts and brown rust starting to show up in susceptible varieties and this needs to be a consideration when choosing the right mix for the T1 sprays,” he explains.
Brown rust in particular can explode when the conditions are right and on susceptible varieties.
“This year 34% of wheats including Zebedee, Cordiale, Solstice, Grafton, JB-Diego and Alchemy have a poor 3 disease rating against brown rust.
“A further 7% of wheats have a 4 rating including Glasgow, Gallant, Mascot, Istabraq, Duxford and Soissons and a further 16% including Hereward, Einstein Panorama and Claire have just a 5 rating. This means that an estimated 56% of wheat in the ground is regarded as being susceptible to this disease.
“Quite a few of these wheats have had their disease susceptibility ratings reduced this year, so all the more reason to be aware of the risk of brown rusts, he says.
Nick points out that another disease prone to significant epidemics, yellow rust will attack varieties such as Robigus that now has a low 2 rating, Glasgow with a 4 rating and Hereward with a 5 rating.
“Mildew maybe worth keeping an eye on, too, as 33% of the wheat area grown has either a 4 or 5 disease rating for mildew. Varieties such as Claire (4 rating), Gallant, Istabraq, Solstice, Humber, Hereward, Oakley, JB Diego Glasgow and Duxford all have a 5 rating.”
Nick considers the triazoles to be the key fungicide group for T1 timing, with the core treatments being based around epoxiconazole and prothioconazole.
“Both actives are strong on Septoria but weaker curatively on rusts, particularly prothioconazole.”
Ends
PRM212
28th April 2009
For further information please contact Nick Myers, ProCam Ltd., Royston, Herts. Telephone: 01763 261592
Issued by Philip Hainey, Proterra Ltd., Stamford, Lincs. Telephone: 01780 756299 |
|
