Wet May could result in high fusarium risk to wheat

Early indications suggest there is potential for 2015 to be a significant fusarium ear blight year if conditions remain favourable.

Last season, 70% of crops had fusarium symptoms, said Fera fusarium expert Phil Jennings. “This suggests there was high inoculum pressure due to favourable spring conditions.”

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The majority of the symptoms were caused by microdochium, with 60% of crops infected. “Last year was the third highest in the past 10 years in terms of the number of crops infected by microdochium.”

But when it came to harvest, Fusarium culmorum and graminearum levels were low, suggesting weather at flowering was not favourable for infection.

With microdochium, only 10% of ears within a crop showed infection and on these, typically only one or two spikelets were infected, so much less than in 2012, where 35% of ears within crops and typically 10-15 spikelets were infected.

So while the pressure from last year (inoculum carryover) is not particularly high, the winter was fairly favourable and not overly cold. “This suits microdochium and to some extent, fusarium too,” Mr Jennings said.

“And now we have seen warm spring conditions. Being relatively dry and mild is good for both microdochium and fusarium.”

Therefore, he believes there is potential for inoculum to build up in crops in the coming weeks.

“This now depends on conditions in May. Fusarium graminearum produces perithecia [fruiting bodies] in crop debris and they need moisture in May to mature and produce spores. The longer-term forecast is wetter, therefore, more conducive to produce spores,” Mr Jennings warned.