24 July 1998

OSR plots offer disease clues

DISENTANGLING oilseed rape plots at Morley Research Centre ahead of harvest has highlighted disease pointers worth bearing in mind when choosing varieties for the coming season.

"We are seeing noticeably more phoma stem canker in Synergy than Apex," says agronomist Ben Freer. "Considering their resistance ratings are only a point apart, with Synergy on 5 and Apex on 6, that is quite surprising." Neither variety received autumn fungicide, but both had an identical spray in the spring.

"There is also quite a lot of alternaria about, which may have affected the seed, so people who are thinking of home-saving may need to get their samples tested for it." The basic £45 NIAB oilseed rape seed test does not cater for the disease. To obtain an assessment of alternaria as well as sclerotinia and canker costs £160, he notes. &#42