POLLEN counts are usually high at this time of year, as any hay fever sufferer knows. Oilseed rape is often blamed for exacerbating symptoms because some scientists have claimed that it is particularly allergenic. But new research has pronounced the bright yellow crop 'not guilty'. A comparison, published in the journal Thorax, of 1,000 people living in areas where oilseed rape is grown and 1,000 living where it is not, has shown that seasonal exacerbations of symptoms were equally common.