The pear leaf blister mite can cause severe damages to pear trees. By their hidden way of living inside
the leaf blisters, the mites are protected from plant protection agents. Until now, oil treatments
in early spring, when the mites leave their hibernation sites and invade the young leaves, are the
only possibility to control these mites. Because of the low temperatures during this period (February/
March) the efficacy of pesticides is often not reliable. The aim of this study was to assess the effects
of sulphur applied after harvest at the time, when mites are leaving the blisters and migrate to
the hibernation sites. The treatments were applied shortly after harvest to benefit from the mild temperatures
in September. Visual controls in following spring showed convincing results: With an efficacy
of 95% (one sulphur application in autumn) or 100% (three sulphur applications in autumn),
respectively, even a decontamination of heavily infested orchards is possible
