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Samples collected from the five HGCA-funded Fusarium CropMonitor sites across the UK show inoculum levels are higher than for several seasons. This includes both toxin-producing species F. graminearum and F. culmorum, as well as non-toxin producing but nonetheless yield sapping Microdochium nivale, says disease specialist Phil Jennings of the Food and Environment Research Agency (Fera).

"Both Fusarium species will have liked the warm, dry early spring, which helped build inoculum on crop debris. The wet April then seems to have splashed F. culmorum spores, in particular, up onto leaves, so we are seeing more of it than usual. We've also seen more Microdochium than for several years, probably due to the relatively mild winter. Wet weather in May will also aid production of F. graminearum ascospores,” he notes.

With disease pressure higher than usual Dr Jennings urges growers to focus on T3 plans. "A Fusaria active triazole will be needed this season. Prothioconazole is certainly best for Fusarium, and metconazole and tebuconazole perform well too. However unlike the others, prothioconazole has also shown good activity on Microdochium, in studies here and on the Continent."

And Bayer's Gareth Bubb reminds growers that a Septoria top up will be needed too. "Even with the efficacy and longevity of a product like Aviator²³⁵Xpro (prothiocoinazole + bixafen) then a foliar element will need to be factored into T3 sprays. Many of these crops will have to go through to August and we all know how much Septoria is about right now.

"However, the rain hasn't just brought disease this spring but the moisture crops need to deliver first class yields. Growers will not want to lose out on this or quality premiums either, so with prothioconazole being the most active Septoria and Fusaria azole it makes sense that it forms the backbone of all T3 sprays this season," he concludes.