Dalgety Trials Highlight Early Variety Differences In Bad Take-All Year

May 2003 - With GS31 root assessments showing worrying levels of early take-all damage in second wheats at Throws Farm, marked varietal differences are already becoming apparent in Dalgety's detailed trials.

At over 6.0, the average late-April take-all Index across all nine varieties in the company's second wheat evaluations measured as part of Monsanto’s national root study indicates a serious level of infection. All the more so for the fact that the trials were sown towards the end of October.

"It's clearly shaping-up to be another damaging take-all year," reported Dalgety arable technical development manager, Mike Jeffes. "So it's not surprising we're already seeing clear differences in infection levels between varieties. Of course, it remains to be seen how these levels will develop over the summer, show-up in whiteheads and affect yields. But the early indications certainly look worrying for growers who didn’t use a take-all seed treatment last autumn.

"It would be wrong to name names at this early stage but we’ve seen two varieties in our Sibutol-only plots with take-all indexes of over 10 at GS 31, with several at 6-8, our most reliable second wheat at around 3, and one indexing just 1.4 – less than a tenth the level of the worst affected, " he pointed out.

Despite the relatively high disease pressure, Mike Jeffes explains that Latitude (silthiofam)-treated plots are keeping early season take-all well in check. At under 2, their average recorded index was less than a third that of the controls. And even the apparently worst-affected varieties indexed below 4 with the seed treatment.

"Given the same sort of summer we had last year, these figures suggest we could well see even more serious take-all losses in untreated crops this season," he stressed. "Coupled with the healthier wheat prices we are looking forward to, this seems set to make seed treatment an especially cost-effective proposition.

"Latitude treatment gave yield advantages of up to 0.66t/ha, depending on variety, in our 2002 trials. Even if yield increases over the controls were no greater this time around, at a feed wheat price £65/t we’d be looking at a benefit of as much as £43/ha on this basis - or more than double the £19 cost of treatment. And for higher value crops, of course, the cost:benefit would be even greater."