Article taken from Agronomist & Arable Farmer Magazine
Arable farmers in the South West should choose appropriate wheat varieties to help cope with the region's high disease pressure and lack of suitable spray days
Farmers attending a recent open day in Somerset found that just a slight delay in fungicide timings could have a major impact on yields, emphasising the importance of selecting varieties with strong resistance to disease, particularly Septoria tritici, the key yield robber in the region. ""The wind and rain have been really challenging this year — it's been hard work to find any spray-ing windows," said host farmer Mark Doble. Growing 162ha of wheat, barley, oilseed rape, beans and potatoes at Hurcott Farm, Seavington, Ilminster, Mr Doble said the timing of operations was absolutely key. ""This year will also show that a fungicide applied to the ear is completely necessary — I wouldn't ever go without one.""
Ron Granger, technical arable manager at plant breeding com-pany Limagrain, said that choosing a variety with a high resistance to septoria is essential in the South West, providing security as a buffer for delayed fungicide applications. In the field-scale trials, sponsored by crop protection company BASF and agronomy advice provider Agrovista, 12 different wheat varieties were grown with differing fungicide programmes, including a control with no treatment at all. ""We can control disease as long as we know a variety's susceptibility, but you can spend more money chasing it than by using a preventative approach," said Mr Granger. According to Paul Haynes, BASF agronomy manager, varieties with good resistance to septoria included Skyfall and Crusoe, LG Sundance, KWS Siskin, Costello and Revelation. This year another damaging disease, yellow rust, has become a big issue in the South West.
""A lot of varieties with supposedly good yellow rust resistance have been infected by a new strain of the disease," said Mr Haynes. Reflection and Britannia had succumbed particularly badly, warned Mike Rastall, regional agronomist at Agrovista. ""Yellow rust is relatively easy to manage with a full fungicide programme, as our trials have shown."" At TO (the first fungicide spray) on 31st March, Mr Rastall recommended chlorothalonil and Ceando. Three further sprays followed, T1 on 24 April, T2 on 22 May and T3 on 8th June, at a total cost of £148/ha. Although the fungicide programmes varied, BASF's new Priaxor EC treatment had worked particularly well against septoria, the key disease in the South West, said Mr Haynes. ""It's triazolefree so you have the flexibility to partner it with other products. The strobilurin pyraclostrobin and the SDHI Xemium have good synergies, and you get the physiological benefits of greening, better water use efficiency and nitrogen uptake," he added.
""With epoxiconazole and fenpropimorph it's a brilliant combination."" Last year a 10-day delay in T1 and T2 applications resulted in a 0.3t/ha average yield drop, said Mr Rastall. ""This year I think we'll see big differences as harvest nears."" The level of septoria and yellow rust in the untreated crops was particularly easy to see. ""Last year the untreated yields averaged 9.9t/ha, while treated yields were 13.5t/ha — in 2014 that difference was even more marked," he added. ""A lot of people are looking to cut back on costs but you just don't know what the weather's going to do — having the insurance, of a full fungicide programme really is worthwhile.”