Codling moth larvae from 23 orchards located in five European countries were tested for their susceptibility/resistance to the Cydia pomonella granulovirus (CpGV-M) in standardized laboratory bioassays. Farmers observed in several of these populations reduced susceptibility to CpGV-M treatment. For each C. pomonella strain, the percentage of larvae surviving CpGV-M concentrations of 104 to 106 OB/ml were calculated 14 days after start of the trial and used for prediction of percentage of resistant individuals in the collected population. The mortality was corrected using Abbott’s formula, with the average mortality determined in the controls of all 14-day trials performed (mortality due to other reasons than virus). In general, the results from the bioassays were in accordance with the observations in the field. Most orchards from which the farmer reported failure of the CpGV-M treatment contained resistant codling moth populations. The percentage of resistant individuals in a population ranged roughly from 30 to 90%. However, in some apparently susceptible populations there were also hints for the presence of a very small fraction of resistant individuals. Several of these European populations were tested for susceptibility to eight insecticides including different classes of insect growth regulators and neurotoxic compounds. High mortality was recorded to most insecticides, independent of resistance to CpGV. A reduced susceptibility to azinphos, diflubenzurone, and tebufenozide was recorded in several populations. Overall, there was no indication for the occurrence of cross-resistance between CpGV-M and insecticides in the tested populations.First laboratory tests showed that populations of C. pomonella resistant to CpGV-M were susceptible to new CpGV strains. This study was funded by the EU, CRAFT project 32857; further information can be found under www.sustaincpgv.eu.