Kan rovkvalstren överleva svensk vinter? : övervintringsstudier på Stratiolaelaps scimitus och Neoseiulus cucumeris

Abstract: Predatory mites have been used as biological control agents in Sweden since the 1970’s, primarily in greenhouse cultivation. There is a risk that the mites establish in the environment. Therefore, a risk analysis needs to be performed. In Sweden, the winter acts as an establishment barrier. Therefore, the cold hardiness is important for determining the establishment potential. A smaller literature review and a lethal temperature experiment was performed for two commonly used mites.. LT50 (lethal temperature, the temperature when 50 % of the population dies) for Stratiolaelaps scimitus was estimated to -5.2 C°. The literature review showed that 1.2 % of of Neoseiulus cucumeris survives a ten weeks period of 2 C° temperature. In total, I concluded that the two species could probably not survive in Sweden. However, more studies are required.