MILDEW SUSCEPTIBILITY IN PEAR PROGENIES

An investigation was carried out in 1986 and 1987 on the susceptibility of pear progenies to powdery mildew /Podosphaera leucotricha/. 'Conference and 'Colorée de Juillet' gave progenies with high mildew resistance, while 'Herzogin Elsa' and the Balsgârd selection BP 1043 /'Johantorp' x 'Doyenné du Comice'/ gave many susceptible progenies. Infection was almost equivalent in the greenhouse and in the field, and the infection rate decreased with increasing age. Infection was higher at a windy site with sandy soil than at a more calm site with rather heavy loam.