Craig Padley, NPZ UK winter oilseed rape breeder, notes that in NPZ UK trials the effects of VSS are highly correlated to the VSS score, and that for each 1-point drop in the stem score, the yield is reduced by 180kg/ha.

 

"Disease levels in our trials are increasing year on year, with symptoms being evident in June and susceptible varieties ripening up to two weeks early, reducing TGW and yield.

 

"In our Recommended List disease observation plots in the same field, we had the Disease Index up to 75 on a 1-100 scale."

 

Michael Shuldham of NPZ UK repeats his explanation that VSS is a soil borne fungus which can cause yield reductions of 30% or even more. There are no fungicide treatments available and the key to managing VSS risk is crop hygiene, optimised establishment conditions and wider rotations. 

 

The final step to control VSS is to look at the AHDB RL ratings to see the significant differences in VSS resistance between varieties. (SEE CHART ATTACHED: ''VERTICILLIUM RATING BY VARIETY').