Take-All Disease at Damaging Levels

Crop disease Take-All reached damaging levels at nine out of the 10 HGCA Recommended List second cereal trial sites this season, according to the first-ever monitoring of the disease in these trials.

The only site to show less than moderate levels of the disease, which can affect most cereals and attacks roots, wasn’t sown until mid-November. Root assessments taken from dedicated plots at three stages over the season by NIAB at the 10 trial sites, from Dorset in the south and west to Perth & Kinross in the north and east, reveal a steady build-up of disease levels in second wheats.

From a level of just under 10 at GS31, the average Take-All Index reached a moderate to high incidence of over 37 by GS65, with high to very high levels recorded at four sites and severe infections at one.

NIAB plant pathologist Bruce Napier said: “Overall, the disease development was in line with what we’ve come to expect following several years of Take-All assessment in second wheat trials. Infections established early on only get worse. But the extent to which they develop to damaging levels fundamentally depends on the weather.

“What this study has allowed us to do is track the way the disease builds up across a range of locations and soil types in the same season. And this has been particularly revealing.

“It has, for instance, highlighted that Take-All can be a serious risk just about anywhere ( on heavy soils as much as on light land, in northern Scotland as much as in East Anglia, from later sowings as much as earlier ones, and in wheat after spring barley as much as in true second wheats. Indeed, the second highest index we recorded was after spring barley at the Dumfries and Galloway site. And the highest, in Norfolk, was on a medium soil type and from an October 21 sowing.

“Our study has also underlined the unpredictable nature of disease development over the season. The site with the lowest Take- All level at GS31 did show the lowest level at GS65 and the site with the highest level at GS31 the highest at GS65. Despite lower than average infection levels early on, however, the Lincolnshire and Perth sites recorded some of the highest eventual indexes.”