Use of thermal data as a screen for the establishment potential of non-native biological control agents in the UK

A series of recent studies have investigated the development, cold tolerance and winter field survival of glasshouse biological control agents that are non-native to the UK: Neoseiulus californicus, Macrolophus caliginosus, Delphastus catalinae, Eretmocerus eremicus and Typhlodromips montdorensis. The combined data sets for these species have been analysed to identify laboratory indices of cold tolerance that correlate with the duration of survival under winter field conditions. A strong correlation was found between the laboratory LTime(50) at 5 degrees C and maximum field survival time. Both N. californicus and M. caliginosus survived substantially longer in the laboratory and in the field than the other species. It is suggested that the LTime(50) at 5 degrees C may provide a reliable 'first stage' screen of establishment potential for candidate non-native biological control agents in the UK.