Last season (2018), more than 1/3rd of the organically managed pome fruit orchards suffered damage from codling moth caterpillars. In practice, codling moth is nowadays controlled in organic cultivation by the mating disruption technique on the one hand and one or more treatments with C. pomonella granulovirus sprayings on the other hand. However, resistance of codling moth to granulovirus products has already been observed several times in other countries. In Belgium, this has never been investigated until now. Therefore, in the first half of 2019 a lab procedure was developed within pcfruit to efficiently and reliably test the sensitivity of codling moth (eggs/caterpillars) to various granulovirus strains. Furthermore, infested fruits were collected from various organic pome fruit growers all over Belgium. After all, (starting) resistance build-up is a local fact, and can therefore vary greatly from location to location. The ultimate goal is to advise organic growers on which control methods are still effective at their orchards.