Writing in Crop Production Magazine, Nick Wall discusses winter wheat fungicide options.
“There’s plenty of septoria on the oldest leaves, but I’m yet to find rust. Mildew could be a big problem on small crops and could also establish quickly on lush growth if crops grow away quickly after a prolonged cold spell.”
“T0 will be vital on backwards crops. Three-leaved plants aren’t going to have time to generate tillers, so we need to look after what we have. I advise CTL alone on these crops unless mildew threatens. On more forward crops I favour CTL plus strobilurin, switching to Cherokee (CTL + cyproconazole + propiconazole) at 1 l/ha on rust susceptible varieties.”
Nick Wall is concerned about eyespot this season, especially on spindly plants. “It won’t take much to take out tillers – we could lose 50%.” Nick also favours Tracker at 1l/ha – he’s concerned about Aviator’s compatibility with CTL, which features in all his T1 sprays. More triazole may be added to the Tracker to bring the level up to a three-quarter rate to boost septoria control. If yellow rust remains a problem, a three-quarter rate of epoxiconazole plus 1 l/ha of CTL, possibly with a strob, will feature. New SDHIs are unlikely to be used at this timing. “Crops looked fantastic last June – we should remember that when deciding what to use this season,” he says. He’ll include prothioconazole if microdochium/fusarium is suspected. “We mustn’t forget we only get 40% control at T3. But trials have shown inclusion of prothioconazole through the programme can reduce final fusarium inoculum.”
In some cases, the T1 spray may be pulled forward from GS32 to GS31,especially where backward crops rush through their growth stages and the T0 is missed. Nick would consider an early T1 in this case, increasing rates to help provide an extra few days of cover that night be required to reach T2. However, backward crops are likely to continue to grow quickly, he adds. “Whatever stage crops are at, flag leaves will emerge at the end of May. Crops might even be easier to manage – if growth is delayed we might see three-week gaps between the timings rather than the five to six weeks we saw last year, when crops advanced early and then stopped.”
Nick Wall used SDHI’s universally at T2 last year, and will do so again. Adexar will go on at 1.25 l/ha, Aviator at 1 l/ha. “I might add a quarter-rate triazole or a strobilurin to boost rust control.”