Summary of 1975 field experiments with advisers: Rape blackleg disease fungicide trials

During 1973 and 1974 a large range of fungicide spray and seed treatment schedules were tested. The 1973 results were, on the whole, not very encouraging, but the very early post-germination spray, two weeks after germination, did indicate a possible means of control. In view of the 1973 results, in the 1974 trials fungicidal sprays were applied early, and a new method of application of fungicide to the seed, known as prilling was used. Using fungicide seed prills and seedless fungicide prills the idea was to have the fungicide mixed with materials which dispersed upon wetting, so releasing and making the fungicide much more readily available for absorption by the plant roots. From the 1974 trials very little was obtained in the way of meaningful results with respect to crown canker levels or harvest yields, due partly to the large variation between replications and the large variation within a single plot owing to late infections giving rise to a patchy type of disease infection development. The fungicides used in the 1974 trials were from old stocks, probably 1971. Some Eastern States researchers suggested at this time that not only did Benlate deteriorate during shelf life but that once moistened, as during the prilling process, the Benlate was then in a form which would no longer properly dissolve, forming only a crude suspension. In order to investigate these claims further trials were set up in 1975