Managing mycotoxins: seminar in UK

A CCFRA-organised seminar, in association with Bayer CropScience, brought together growers, grain end users and scientists at the East of England showground, Peterborough, to discuss new developments in managing mycotoxins.

Fungicides alone cannot be relied on

Fungicide sprays alone cannot be relied on for fusarium and DON mycotoxin control, Masstock Arable agronomist Andrew Richards told the meeting.

The introduction in 2006 of a maximum DON level for wheat set an industry benchmark and this season’s experience had shown that this level could be exceeded in the UK, he said.

With two per cent of wheat samples exceeding the 1250ppb limit for DON this harvest, according to AIC/HGCA/ nabim monitoring results, there could be 300,000 tonnes of wheat that cannot enter the human food chain, said Mr Richards.

He questioned whether UK farmers would have to move towards continental-type fungicide programmes, where proportionately more fungicide was applied at the T3 timing and less at T1 in particular, to ensure that their grain was saleable.

BASF survey figures have indicated that over 50 per cent of growers do not apply a T3 to their wheat.

Grower and agronomists could not rely on fungicides as their main source of fusarium control, he said. Secondary growth in many crops harvested this year resulted in a flowering period of around 28 days.

Furthermore, a lot of “beefed up” T3 sprays went on early as growers struggled to control brown rust.

“It would have been impossible to give adequate control of fusarium with a single ear spray,” said Mr Richards. Rotation, cultivations and early season disease management all influenced fusarium control, he said.

Commenting on the influence of the tillage system he said that analysis of over-yeared wheat straw under oilseed rape canopies in early July this year showed evidence of fusarium graminearum.

This would have been of low risk to the following wheat crop but was it a source of infection for neighbouring wheat crops this season? “I’m not sure but it is a study that needs to be done,” said Mr Richards.

Querying the relevance of HGCA Recommended List fusarium resistance ratings he described how, in Masstock ‘Smart farming’ trials this year, some varieties with good resistance ratings had shown high levels of fusarium infection in fungicide treated and untreated trials.

Resistance testing was based on inoculation work, there was historically not enough natural infection for field assessment and there were no varieties with really good resistance, he said.

“As agronomists and farmers we cannot rely on a T3 fungicide to adequately control fusarium and DON levels. We need a number of questions answered on factors affecting fusarium development and we then need to develop an integrated approach to its management.

“In the future I do not want to be the agronomist who has to tell a farmer that he has 1,000 tonnes of unsaleable wheat.”