Appraisal of McAlpine’s Success

Abstract

McAlpine (1910) had recognised that bitter pit was a physiological disorder prior to 1910, such problems not having been recognised previously in Australia. According to Ainsworth (1981), little was known about non-parasitic diseases prior to the twentieth century. He pointed out that Paul Soraurer A1 was the first to draw particular attention to this group of what McAlpine referred to as ‘Constitutional Disorders’, and that by the time the third edition of Soraurer’s Handbuch der Pflanzenkrankheiten (1909) was republished from 1905 to 1913 one volume was devoted solely to physiological disorders. Ainsworth drew attention to the generally limited space devoted to these diseases in texts on plant pathology, and made the point that plant pathologists generally disregard them, preferring to hand them over to plant physiologists or others. Ainsworth also drew attention to the lack of knowledge about the importance of minor and trace elements in plant nutrition before the 1920s so there was no base from which to study physiological disorders involving nutritional imbalances. Lack of boron in highly leached sandy soils was reported and confirmed as important for various crops between 1910 and 1923, and magnesium deficiency was identified as a cause of chlorosis in crops, including apples, growing in leached sandy soils. Over the next two decades, various experiments with boron and magnesium singly and in various combinations with major and minor elements were reported but usually with inconclusive of conflicting results (Bunemann 1972). McAlpine included both boron and magnesium in his manurial experiments during the bitter pit investigation, but without positive outcomes.