Augmentative biological control, which refers to frequent releases of mass produced natural enemies, is well developedin the greenhouse cropping systems and many successful cases have been reported worldwide. The most robust biocontrolsystems are based on the principle of established populations of natural enemies before invasions of pests occur. However,the natural enemies that are commercially available do not establish well in all crops, which can be caused by a lackof food sources, a lack of oviposition sites or shelter, or because of an unsuitable microclimate. These problems can besolved by selecting new species of natural enemies that are better adapted to the crop and/or by providing the resourcesthat natural enemies need to survive and reproduce in the crop. Here we present some results of studies that may contributeto this “standing army approach” in biocontrol, based on the use of banker plants, nectar plants, rearing sachets, foodsprays and alternative prey applications.in the greenhouse cropping systems and many successful cases have been reported worldwide. The most robust biocontrolsystems are based on the principle of established populations of natural enemies before invasions of pests occur. However,the natural enemies that are commercially available do not establish well in all crops, which can be caused by a lackof food sources, a lack of oviposition sites or shelter, or because of an unsuitable microclimate. These problems can besolved by selecting new species of natural enemies that are better adapted to the crop and/or by providing the resourcesthat natural enemies need to survive and reproduce in the crop. Here we present some results of studies that may contributeto this “standing army approach” in biocontrol, based on the use of banker plants, nectar plants, rearing sachets, foodsprays and alternative prey applications.

• Gerben J. Messelink(Wageningen University & Research, BU Greenhouse Horticulture, the Netherlands)