CEREAL GROWERS have been warned not to rely too heavily on seed testing when deciding whether to use a dressing.

Testing seed, especially farm-saved samples, give a good idea of seed health, but there are many other factors that determine emergence success, said Syngenta.

“We welcome the new rapid test and are very much in favour of targeting pesticides where they are needed,” said the company‘s seed treatment business manager Martin Weiss.

“But not all the pathogens that seed face are seed-borne.”

Soil-borne diseases, such as soil-borne bunt and blue mould, would not be picked up in a seed test, but can cause considerable establishment problems, he warned.

“Blue mould was very prevalent last autumn when seed sat in the ground for up to six weeks in dry conditions before germinating.”

There is still a justifiable case for using a seed dressing as an insurance, even where tests reveal the seed is free from disease, added Mr Weiss.

“Part of the reason the level of establishment diseases is so low is the widespread use of effective seed treatments.”

At a typical cost of around £6/ha and an application rate of 20g/ha, seed treatments are a relatively low-cost, targeted route to keeping a crop clean, he added.

“It‘s also important to use a chemical with a different mode of action and no resistance problems,” said Mr Weiss.