Fungal pathogens thrive on oilseed rape and the spores can be transported large distances by the wind. Spores from field fungi are well documented for causing allergy and are particularly hazardous to asthmatics.
In 1994, Soutar reported: Among the predominant spores recorded, counts of Cladosporium, Sporobolomyces and Tilletiopsis were generally higher in the oilseed rape than non-oilseed rape areas. Counts of Leptosphaeria and Pullularia were roughly similar at both sites. The number of basidiospores recorded was similar at both sites, apart from the end of April and beginning of May when counts were very much higher in the oilseed rape area. Although Alternaria and Botrysis are among the major pathogens of oilseed rape, they were recorded only on very few occasions and in very low numbers at both sites.
A study by Galloway (1996), reported in a thesis, investigated the role of fungal pathogens of oilseed rape, Alternaria alternata and Botrysis cineria, as possible causes of oilseed rape related allergy. The study was conducted in 1989 and 1990 in the Letham/Bowriefauld area of Angus in Tayside, an area with over 6000 hectares of oilseed rape.
In 2000, Galloway reported: Moulds growing on the oilseed rape crop may also be responsible for some of the symptoms. Parratt (1990) found that RAST positivity for mixed moulds was as high as 17% and sensitivity to Alternaria alternata, which is commonly found on oilseed rape, has been shown to be a risk factor for sudden, severe episodes of asthma (O'Halleren MT 1991).
Work carried out in our laboratory has shown that exposure to a common fungal parasite of oilseed rape, Botrytis cinerea, occurs frequently in rural dwellers and that IgE sensitization occurs in a signifcant number of those exposed when susceptible oilseed rape crop strains are cultivated (Galloway 1996). Pre-season measurement showed that 11.1% of participants had detectable IgE antibodies to this fungus and 36.5% were positive at the post-season recall.
Author - Armitage; copyright 2007