A comparison of the Ulster, New Zealand, and Ottawa methods of seed examination for the presence of Polyspora lini Laff., the cause of stem-break and browning disease of flax, showed great variation in the percentage of infection obtained, depending upon the method used. The Ulster method, in which the seed is not treated before it is plated, does not differentiate deep-seated infection from superficial infection of the seed, but has proved satisfactory in actual practice with seed samples that are not contaminated seriously by saprophytic fungi. The New Zealand method, by which surface contamination is supposedly removed by washing the seed in running water, has not been found reliable. The Ottawa method, by which the seed is surface sterilized before it is plated, does not indicate the degree of superficial infection, but does give the percentage of deep-seated infection, and hence it indicates the suitability of the seed for planting purposes if the seed is treated with a fungicide. It is suggested that a centrifuge test combined with the Ottawa plating method would provide a better index of the health condition of flax seed as far as disease caused by. P. lini is concerned.
Identification and Detection of Maize Seed Borne Pathogens using Different Seed Testing Methods