Varietal differences to Verticillium wilt in oilseed rape observed in the field

This summer independent agronomist John Tunaley has observed dramatic differences in the field between oilseed rape varieties to the increasingly important disease in winter oilseed rape, Verticillium wilt. The variety Alienor appears to be showing strong in-field resistance, reflecting the ADAS trials work.

Advising farmers in Suffolk, Norfolk and Essex, John says that Verticillium wilt is a massive problem this year for those growing rape intensively. "It’s hard not to exaggerate the situation, but I have never seen such high levels of infection before. But symptoms are only recently shown up in the field. I have been walking fields of oilseed rape every 7 days in order to time desiccation treatments accurately. Fifteen days ago I wasn’t seeing much Verticillium but now the symptoms - long vertical toffee brown stripes from soil level running most of the length of the stem - are very easily seen and have escalated in a very short time frame. More recently the symptoms have developed further to produce long vertical grey pin stripes with black micro sclerotia on the stem surface."

John has also observed significant differences between varieties grown under the same conditions. "In particular I have noticed that the variety Alienor appears to be able to resist Verticillium, much better than any variety being grown by my clients. Alongside varieties such as DK Cabernet and Sesame that are very badly affected by Verticillium, Alienor stands out as being green and really lacking this disease. On one of my farms the Cabernet which is being grown in a 1 in 5 rotation has at least 50-60% level of infection, whereas the Alienor grown on a tighter rotation of 1 in 3 has less than 5% - a dramatic visual comparison."

Neil Groom of Grainseed says that John Tunaley’s experience reflects his knowledge of the resistance of Es Alienor in France where disease levels are much higher than in the UK as well as the variety comparison trials undertaken by ADAS over the last two years. "With more and more Verticillium being seen in oilseed rape crops, growers should consider planting resistant varieties such as Alienor, as there are no proven chemical treatments to fall back on."

John Tunaley points out that Verticillium is a disease of intensively grown rape and his observations would suggest that you have to be growing rape no more than 1 year in 6 to have any chance of avoiding this disease.

Neil points out that Alienor has already been widely adopted by growers because of its very early maturity. "Alienor matures 7-10 days earlier than Castille, which allows much more opportunity for seedbed preparation and stale seedbeds as well as timely entry for following crops. Its strong Verticillium wilt resistance, which we understand will be confirmed this year by Dr Peter Gladders varietal monitoring trials, adds another important feature to this variety. Alienor already has an 6 rating for Light Leaf Spot and a 7 rating for Phoma stem canker giving it a combined disease resistance package that is very hard to beat."