San José Scale in Deciduous Fruit Orchards of Some European Countries (Survey of Scale Insect Infestations in European Orchards No. IV)

Fruit tree branch and bark samples have been collected from several European countries (Czechoslovakia, Greece, Hungary, Poland, Turkey, European part of USSR) from apple, pear, peach, plum, cherry and sour cherry. Twenty-five scale insect species were found in the samples. Distribution maps of Quadra & pidiotus perniciosus on different fruit species are given. No significant changes in the distribution of this species in Central Europe can be observed in the last 30 years. Q. perniciosus is present in higher density on apple wherever it occurs, and is less frequent on pears and plums. It is frequent on peach and sometimes on cherry, but generally at low densities. It is rare on sour cherry.