Autumn applications of sulphur: a new approach to control the pear leaf blister mite Eriophyes pyri | Applications de soufre en automne: une nouvelle maniere de lutter contre l'eriophyide a galles du poirier
Daniel, C. | Wyss, E.(Institut de recherches de l'agriculture biologique Frick (IRAB), Frick (Switzerland)) | Linder, Ch.
The pear leaf blister mite can cause severe damage to pear leaves and young fruits in some regions. Due to hidden living inside leaf blisters, the mites are largely protected against the impact of plant protecting agents. Until now, treatments with mineral oil in early spring, during the time when the mites leave their hibernation sites under the bud scales to invade the young leaves and blossoms, were the only possibility to control these mites in Swiss organic fruit growing. The aim of this study was to examine the effects of sulphur, mineral oil and Surround®WP applied after harvest, at the time when the mites leave their blisters and migrate to their hibernation sites. These different treatments were applied shortly after harvest to benefit of mild temperatures of September. Counting the number of mites after dissection of the buds in laboratory in autumn and spring showed a good efficacy for all treatments. But at visual spring control during bloom, these results could not be verified for all treatments. Only the sulphur-treated trees were virtually free of blisters at spring time. With an efficacy of 95% (one application) or 100% (three applications), even heavily infested orchards may be cleaned-up.
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