Break crops merit effective disease control – TAG

Few growers will leave disease control in the 2008 oilseed crop to chance, says The Arable Group with the publication of its second Spring Strategies document.

With ex-farm prices at £300/t, inputs can be raised without having to squeeze margins too much, the independent agronomy service says – sclerotinia control potentially being the biggest winner. Beans and peas will also benefit from a strategic disease risk assessment, it suggests.

"2007 saw a surprisingly high level of sclerotinia in many parts of the country," points out Richard Overthrow, who compiled the Spring Strategies guide from TAG's research findings at 23 sites throughout England.

"Based on that experience, many growers decided that flowering sprays would become a routine input," he says, "and most growers probably intend to spray at this timing. However, TAG trials suggest that this is the least responsive timing."

Mr Overthrow says that before making routine sprays, growers should assess the risk factors – frequency of rape in the rotation, soil temperature and moisture, and timing and length of flowering period.

"Even if the decision comes down in favour of spraying, TAG trials suggest a fairly inexpensive choice can nevertheless deliver good results."

Meanwhile, chocolate spot , rust and downy mildew present the main obstacles to a disease-free bean crop, Mr Overthrow explains, with downy mildew becoming an increasing problem in winter beans. "That's best controlled by hot, dry weather, something we didn't see a lot of in late spring 2007.

"Last year saw more success from a two-spray approach – T1 at early to mid flowering, followed by a second spray three or four weeks later."

Full, in-depth information about rates and recommendations on break crops and cereals is contained within the Spring Strategies document, sent to TAG members this week.