Black-end of pear: Problem is subject of extensive field and laboratory studies
L. D. Davis, Experiment Station, Davis.
California Agriculture 2(6):10-15. DOI: 10.3733/ca.v002n06p10.
Not available – first paragraph follows:
Intensive investigations have been conducted in the field and in the laboratory since about 1930 regarding black-end or hard-end condition of pears and the relation of the rootstock to the incidence of the disease.
L. D. Davis is Professor of Pomology and Pomologist in the Experiment Station, Davis.