Late autumn treatment with sulphur or rapeseed oil as partof a management strategy for the raspberry leaf and bud mitePhyllocoptes gracilis in ‘Glen Ample’

Abstract: Glen Ample is the main raspberry cultivar in Norway. This cultivar is very susceptibleto the raspberry leaf and bud mite Phyllocoptes gracilis, and serious damage on both leaves andfruits are common. The only documented control measure available has been fenpyroximate(Ortus/Danitron), a substance that can only be used once per growing season, which is notsufficient to keep P. gracilis below damaging population levels. Nor can it be used by organicgrowers. In a search for alternative control measures we conducted trials with rapeseed oil(emulsified with soft soap) and sulphur (Thiovit Jet) in heavily infested fields. The effect wasmeasured by assessing leaf damage and counting mites overwintering in the buds. The resultsimply that post harvest spraying with vegetable oils or sulphur targeting overwintering females inthe buds is a very valuable component of a management strategy for the leaf and bud mite in‘Glen Ample’.